Ack transmission using multilink

ABSTRACT

In a wireless local area network system, a receiving device may receive a Block Acknowledgment Request (BAR) frame including information related to a link for which an ACK is requested, and transmit a Block ACK (BA) frame on the basis of the BAR frame. The receiving device is a Multi-Link Device (MLD), which supports communication over multiple links. Each link of the multiple links can be configured based on 2.4 GHz band, 5 GHz band, and/or 6 GHz band defined in a conventional wireless local area network system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage filing under 35 U.S.C. 371 ofInternational Application No. PCT/KR2020/010891, filed on Aug. 14, 2020,which claims the benefit of earlier filing date and right of priority toKorean Application No. 10-2019-0168227, filed on Dec. 16, 2019, thecontents of which are all hereby incorporated by reference herein intheir entireties.

BACKGROUND Field of the Disclosure

The present specification relates to a method of transmitting anacknowledgment (ACK) signal using a multi-link in a wireless local areanetwork (WLAN) system.

Related Art

A wireless local area network (WLAN) has been improved in various ways.For example, the IEEE 802.11ax standard proposed an improvedcommunication environment using orthogonal frequency division multipleaccess (OFDMA) and downlink multi-user multiple input multiple output(DL MU MIMO) techniques.

The present specification proposes a technical feature that can beutilized in a new communication standard. For example, the newcommunication standard may be an extreme high throughput (EHT) standardwhich is currently being discussed. The EHT standard may use anincreased bandwidth, an enhanced PHY layer protocol data unit (PPDU)structure, an enhanced sequence, a hybrid automatic repeat request(HARQ) scheme, or the like, which is newly proposed. The EHT standardmay be called the IEEE 802.11be standard.

SUMMARY Technical Solutions

According to various embodiments of the present disclosure, a methodperformed by a receiving device in a wireless local area network systemmay include technical features related to a method of transmitting aresponse signal using a multi-link. A receiving device may receive firstdata through a first link and receive second data through a second link,from a transmitting device. A receiving device may receive a first blockacknowledgment request (BAR) frame through the first link and receive asecond BAR frame through the second link, from the transmitting device.The first BAR frame and the second BAR frame include information relatedto a link for which an acknowledgement (ACK) is requested. A receivingdevice may transmit a first block acknowledgment (BA) frame through thefirst link and transmit a second BA frame through the second link.

Technical Effects

According to an example of the present specification, a receiving devicemay receive data through a plurality of links, and may receive a BARframe through a plurality of links. The BAR frame received through eachlink may include link information related to ACK information to betransmitted through each link by the receiving device. For example, ifthe BAR frame includes information related to the first link and thesecond link, the receiving device may transmit the BA frame includingACK information for data received through the first link and the secondlink. Accordingly, the transmitting device can flexibly receive desiredACK information through a desired link.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of a transmitting apparatus and/or receivingapparatus of the present specification.

FIG. 2 is a conceptual view illustrating the structure of a wirelesslocal area network (WLAN).

FIG. 3 illustrates a general link setup process.

FIG. 4 illustrates an example of a PPDU used in an IEEE standard.

FIG. 5 illustrates a layout of resource units (RUs) used in a band of 20MHz.

FIG. 6 illustrates a layout of RUs used in a band of 40 MHz.

FIG. 7 illustrates a layout of RUs used in a band of 80 MHz.

FIG. 8 illustrates a structure of an HE-SIG-B field.

FIG. 9 illustrates an example in which a plurality of user STAs areallocated to the same RU through a MU-MIMO scheme.

FIG. 10 illustrates an operation based on UL-MU.

FIG. 11 illustrates an example of a trigger frame.

FIG. 12 illustrates an example of a common information field of atrigger frame.

FIG. 13 illustrates an example of a subfield included in a per userinformation field.

FIG. 14 describes a technical feature of the UORA scheme.

FIG. 15 illustrates an example of a channel used/supported/definedwithin a 2.4 GHz band.

FIG. 16 illustrates an example of a channel used/supported/definedwithin a 5 GHz band.

FIG. 17 illustrates an example of a channel used/supported/definedwithin a 6 GHz band.

FIG. 18 illustrates an example of a PPDU used in the presentspecification.

FIG. 19 illustrates an example of a modified transmission device and/orreceiving device of the present specification.

FIG. 20 shows an example of channel bonding.

FIG. 21 is a diagram illustrating an embodiment of multi-linktransmission.

FIG. 22 is a diagram showing an example of synchronous multi-linktransmission.

FIG. 23 is a diagram showing an example of synchronous multi-linktransmission.

FIGS. 24 and 25 are diagrams illustrating an embodiment of a synchronousmulti-link ACK transmission method.

FIGS. 26 to 33 show embodiments of a method for transmitting asynchronous multi-link ACK.

FIG. 34 is a diagram showing an example of asynchronous multi-linktransmission.

FIG. 35 is a diagram showing an example of asynchronous multi-linktransmission.

FIGS. 36 and 37 are diagrams illustrating an example of an asynchronousmulti-link transmission method.

FIGS. 38 to 41 show embodiments of an asynchronous multi-link ACKtransmission method.

FIG. 42 is a diagram illustrating an embodiment of a PPDU used for datatransmission.

FIG. 43 is a diagram illustrating an embodiment of a PPDU used for datatransmission.

FIG. 44 is a diagram illustrating an embodiment of a PPDU used for datatransmission.

FIG. 45 is a diagram illustrating an embodiment of a PPDU used as a BAframe.

FIG. 46 is a diagram illustrating an embodiment of a PPDU used as a BAframe.

FIG. 47 is a diagram illustrating an embodiment of a PPDU used as a BARframe.

FIG. 48 is a diagram illustrating an embodiment of an operation of areceiving device.

FIG. 49 is a diagram illustrating an embodiment of an operation of atransmitting device.

DETAILED DESCRIPTION

In the present specification, “A or B” may mean “only A”, “only B” or“both A and B”. In other words, in the present specification, “A or B”may be interpreted as “A and/or B”. For example, in the presentspecification, “A, B, or C” may mean “only A”, “only B”, “only C”, or“any combination of A, B, C”.

A slash (/) or comma used in the present specification may mean“and/or”. For example, “A/B” may mean “A and/or B”. Accordingly, “A/B”may mean “only A”, “only B”, or “both A and B”. For example, “A, B, C”may mean “A, B, or C”.

In the present specification, “at least one of A and B” may mean “onlyA”, “only B”, or “both A and B”. In addition, in the presentspecification, the expression “at least one of A or B” or “at least oneof A and/or B” may be interpreted as “at least one of A and B”.

In addition, in the present specification, “at least one of A, B, and C”may mean “only A”, “only B”, “only C”, or “any combination of A, B, andC”. In addition, “at least one of A, B, or C” or “at least one of A, B,and/or C” may mean “at least one of A, B, and C”.

In addition, a parenthesis used in the present specification may mean“for example”. Specifically, when indicated as “control information(EHT-signal)”, it may denote that “EHT-signal” is proposed as an exampleof the “control information”. In other words, the “control information”of the present specification is not limited to “EHT-signal”, and“EHT-signal” may be proposed as an example of the “control information”.In addition, when indicated as “control information (i.e., EHT-signal)”,it may also mean that “EHT-signal” is proposed as an example of the“control information”.

Technical features described individually in one figure in the presentspecification may be individually implemented, or may be simultaneouslyimplemented.

The following example of the present specification may be applied tovarious wireless communication systems. For example, the followingexample of the present specification may be applied to a wireless localarea network (WLAN) system. For example, the present specification maybe applied to the IEEE 802.11a/g/n/ac standard or the IEEE 802.11axstandard. In addition, the present specification may also be applied tothe newly proposed EHT standard or IEEE 802.11be standard. In addition,the example of the present specification may also be applied to a newWLAN standard enhanced from the EHT standard or the IEEE 802.11bestandard. In addition, the example of the present specification may beapplied to a mobile communication system. For example, it may be appliedto a mobile communication system based on long term evolution (LTE)depending on a 3^(rd) generation partnership project (3GPP) standard andbased on evolution of the LTE. In addition, the example of the presentspecification may be applied to a communication system of a 5G NRstandard based on the 3GPP standard.

Hereinafter, in order to describe a technical feature of the presentspecification, a technical feature applicable to the presentspecification will be described.

FIG. 1 shows an example of a transmitting apparatus and/or receivingapparatus of the present specification.

In the example of FIG. 1 , various technical features described belowmay be performed. FIG. 1 relates to at least one station (STA). Forexample, STAs 110 and 120 of the present specification may also becalled in various terms such as a mobile terminal, a wireless device, awireless transmit/receive unit (WTRU), a user equipment (UE), a mobilestation (MS), a mobile subscriber unit, or simply a user. The STAs 110and 120 of the present specification may also be called in various termssuch as a network, a base station, a node-B, an access point (AP), arepeater, a router, a relay, or the like. The STAs 110 and 120 of thepresent specification may also be referred to as various names such as areceiving apparatus, a transmitting apparatus, a receiving STA, atransmitting STA, a receiving device, a transmitting device, or thelike.

For example, the STAs 110 and 120 may serve as an AP or a non-AP. Thatis, the STAs 110 and 120 of the present specification may serve as theAP and/or the non-AP.

The STAs 110 and 120 of the present specification may support variouscommunication standards together in addition to the IEEE 802.11standard. For example, a communication standard (e.g., LTE, LTE-A, 5G NRstandard) or the like based on the 3GPP standard may be supported. Inaddition, the STA of the present specification may be implemented asvarious devices such as a mobile phone, a vehicle, a personal computer,or the like. In addition, the STA of the present specification maysupport communication for various communication services such as voicecalls, video calls, data communication, and self-driving(autonomous-driving), or the like.

The STAs 110 and 120 of the present specification may include a mediumaccess control (MAC) conforming to the IEEE 802.11 standard and aphysical layer interface for a radio medium.

The STAs 110 and 120 will be described below with reference to asub-figure (a) of FIG. 1 .

The first STA 110 may include a processor 111, a memory 112, and atransceiver 113. The illustrated process, memory, and transceiver may beimplemented individually as separate chips, or at least twoblocks/functions may be implemented through a single chip.

The transceiver 113 of the first STA performs a signaltransmission/reception operation. Specifically, an IEEE 802.11 packet(e.g., IEEE 802.11a/b/g/n/ac/ax/be, etc.) may be transmitted/received.

For example, the first STA 110 may perform an operation intended by anAP. For example, the processor 111 of the AP may receive a signalthrough the transceiver 113, process a reception (RX) signal, generate atransmission (TX) signal, and provide control for signal transmission.The memory 112 of the AP may store a signal (e.g., RX signal) receivedthrough the transceiver 113, and may store a signal (e.g., TX signal) tobe transmitted through the transceiver.

For example, the second STA 120 may perform an operation intended by anon-AP STA. For example, a transceiver 123 of a non-AP performs a signaltransmission/reception operation. Specifically, an IEEE 802.11 packet(e.g., IEEE 802.11a/b/g/n/ac/ax/be packet, etc.) may betransmitted/received.

For example, a processor 121 of the non-AP STA may receive a signalthrough the transceiver 123, process an RX signal, generate a TX signal,and provide control for signal transmission. A memory 122 of the non-APSTA may store a signal (e.g., RX signal) received through thetransceiver 123, and may store a signal (e.g., TX signal) to betransmitted through the transceiver.

For example, an operation of a device indicated as an AP in thespecification described below may be performed in the first STA 110 orthe second STA 120. For example, if the first STA 110 is the AP, theoperation of the device indicated as the AP may be controlled by theprocessor 111 of the first STA 110, and a related signal may betransmitted or received through the transceiver 113 controlled by theprocessor 111 of the first STA 110. In addition, control informationrelated to the operation of the AP or a TX/RX signal of the AP may bestored in the memory 112 of the first STA 110. In addition, if thesecond STA 120 is the AP, the operation of the device indicated as theAP may be controlled by the processor 121 of the second STA 120, and arelated signal may be transmitted or received through the transceiver123 controlled by the processor 121 of the second STA 120. In addition,control information related to the operation of the AP or a TX/RX signalof the AP may be stored in the memory 122 of the second STA 120.

For example, in the specification described below, an operation of adevice indicated as a non-AP (or user-STA) may be performed in the firstSTA 110 or the second STA 120. For example, if the second STA 120 is thenon-AP, the operation of the device indicated as the non-AP may becontrolled by the processor 121 of the second STA 120, and a relatedsignal may be transmitted or received through the transceiver 123controlled by the processor 121 of the second STA 120. In addition,control information related to the operation of the non-AP or a TX/RXsignal of the non-AP may be stored in the memory 122 of the second STA120. For example, if the first STA 110 is the non-AP, the operation ofthe device indicated as the non-AP may be controlled by the processor111 of the first STA 110, and a related signal may be transmitted orreceived through the transceiver 113 controlled by the processor 111 ofthe first STA 110. In addition, control information related to theoperation of the non-AP or a TX/RX signal of the non-AP may be stored inthe memory 112 of the first STA 110.

In the specification described below, a device called a(transmitting/receiving) STA, a first STA, a second STA, a STA1, a STA2,an AP, a first AP, a second AP, an AP1, an AP2, a(transmitting/receiving) terminal, a (transmitting/receiving) device, a(transmitting/receiving) apparatus, a network, or the like may imply theSTAs 110 and 120 of FIG. 1 . For example, a device indicated as, withouta specific reference numeral, the (transmitting/receiving) STA, thefirst STA, the second STA, the STA1, the STA2, the AP, the first AP, thesecond AP, the AP1, the AP2, the (transmitting/receiving) terminal, the(transmitting/receiving) device, the (transmitting/receiving) apparatus,the network, or the like may imply the STAs 110 and 120 of FIG. 1 . Forexample, in the following example, an operation in which various STAstransmit/receive a signal (e.g., a PPDU) may be performed in thetransceivers 113 and 123 of FIG. 1 . In addition, in the followingexample, an operation in which various STAs generate a TX/RX signal orperform data processing and computation in advance for the TX/RX signalmay be performed in the processors 111 and 121 of FIG. 1 . For example,an example of an operation for generating the TX/RX signal or performingthe data processing and computation in advance may include: 1) anoperation ofdetermining/obtaining/configuring/computing/decoding/encoding bitinformation of a sub-field (SIG, STF, LTF, Data) included in a PPDU; 2)an operation of determining/configuring/obtaining a time resource orfrequency resource (e.g., a subcarrier resource) or the like used forthe sub-field (SIG, STF, LTF, Data) included the PPDU; 3) an operationof determining/configuring/obtaining a specific sequence (e.g., a pilotsequence, an STF/LTF sequence, an extra sequence applied to SIG) or thelike used for the sub-field (SIG, STF, LTF, Data) field included in thePPDU; 4) a power control operation and/or power saving operation appliedfor the STA; and 5) an operation related todetermining/obtaining/configuring/decoding/encoding or the like of anACK signal. In addition, in the following example, a variety ofinformation used by various STAs fordetermining/obtaining/configuring/computing/decoding/decoding a TX/RXsignal (e.g., information related to a field/subfield/controlfield/parameter/power or the like) may be stored in the memories 112 and122 of FIG. 1 .

The aforementioned device/STA of the sub-figure (a) of FIG. 1 may bemodified as shown in the sub-figure (b) of FIG. 1 . Hereinafter, theSTAs 110 and 120 of the present specification will be described based onthe sub-figure (b) of FIG. 1 .

For example, the transceivers 113 and 123 illustrated in the sub-figure(b) of FIG. 1 may perform the same function as the aforementionedtransceiver illustrated in the sub-figure (a) of FIG. 1 . For example,processing chips 114 and 124 illustrated in the sub-figure (b) of FIG. 1may include the processors 111 and 121 and the memories 112 and 122. Theprocessors 111 and 121 and memories 112 and 122 illustrated in thesub-figure (b) of FIG. 1 may perform the same function as theaforementioned processors 111 and 121 and memories 112 and 122illustrated in the sub-figure (a) of FIG. 1 .

A mobile terminal, a wireless device, a wireless transmit/receive unit(WTRU), a user equipment (UE), a mobile station (MS), a mobilesubscriber unit, a user, a user STA, a network, a base station, aNode-B, an access point (AP), a repeater, a router, a relay, a receivingunit, a transmitting unit, a receiving STA, a transmitting STA, areceiving device, a transmitting device, a receiving apparatus, and/or atransmitting apparatus, which are described below, may imply the STAs110 and 120 illustrated in the sub-figure (a)/(b) of FIG. 1 , or mayimply the processing chips 114 and 124 illustrated in the sub-figure (b)of FIG. 1 . That is, a technical feature of the present specificationmay be performed in the STAs 110 and 120 illustrated in the sub-figure(a)/(b) of FIG. 1 , or may be performed only in the processing chips 114and 124 illustrated in the sub-figure (b) of FIG. 1 . For example, atechnical feature in which the transmitting STA transmits a controlsignal may be understood as a technical feature in which a controlsignal generated in the processors 111 and 121 illustrated in thesub-figure (a)/(b) of FIG. 1 is transmitted through the transceivers 113and 123 illustrated in the sub-figure (a)/(b) of FIG. 1 . Alternatively,the technical feature in which the transmitting STA transmits thecontrol signal may be understood as a technical feature in which thecontrol signal to be transferred to the transceivers 113 and 123 isgenerated in the processing chips 114 and 124 illustrated in thesub-figure (b) of FIG. 1 .

For example, a technical feature in which the receiving STA receives thecontrol signal may be understood as a technical feature in which thecontrol signal is received by means of the transceivers 113 and 123illustrated in the sub-figure (a) of FIG. 1 . Alternatively, thetechnical feature in which the receiving STA receives the control signalmay be understood as the technical feature in which the control signalreceived in the transceivers 113 and 123 illustrated in the sub-figure(a) of FIG. 1 is obtained by the processors 111 and 121 illustrated inthe sub-figure (a) of FIG. 1 . Alternatively, the technical feature inwhich the receiving STA receives the control signal may be understood asthe technical feature in which the control signal received in thetransceivers 113 and 123 illustrated in the sub-figure (b) of FIG. 1 isobtained by the processing chips 114 and 124 illustrated in thesub-figure (b) of FIG. 1 .

Referring to the sub-figure (b) of FIG. 1 , software codes 115 and 125may be included in the memories 112 and 122. The software codes 115 and126 may include instructions for controlling an operation of theprocessors 111 and 121. The software codes 115 and 125 may be includedas various programming languages.

The processors 111 and 121 or processing chips 114 and 124 of FIG. 1 mayinclude an application-specific integrated circuit (ASIC), otherchipsets, a logic circuit and/or a data processing device. The processormay be an application processor (AP). For example, the processors 111and 121 or processing chips 114 and 124 of FIG. 1 may include at leastone of a digital signal processor (DSP), a central processing unit(CPU), a graphics processing unit (GPU), and a modulator and demodulator(modem). For example, the processors 111 and 121 or processing chips 114and 124 of FIG. 1 may be SNAPDRAGON™ series of processors made byQualcomm®, EXYNOS™ series of processors made by Samsung®, A series ofprocessors made by Apple®, HELIO™ series of processors made byMediaTek®, ATOM™ series of processors made by Intel® or processorsenhanced from these processors.

In the present specification, an uplink may imply a link forcommunication from a non-AP STA to an SP STA, and an uplinkPPDU/packet/signal or the like may be transmitted through the uplink. Inaddition, in the present specification, a downlink may imply a link forcommunication from the AP STA to the non-AP STA, and a downlinkPPDU/packet/signal or the like may be transmitted through the downlink.

FIG. 2 is a conceptual view illustrating the structure of a wirelesslocal area network (WLAN).

An upper part of FIG. 2 illustrates the structure of an infrastructurebasic service set (BSS) of institute of electrical and electronicengineers (IEEE) 802.11.

Referring the upper part of FIG. 2 , the wireless LAN system may includeone or more infrastructure BSSs 200 and 205 (hereinafter, referred to asBSS). The BSSs 200 and 205 as a set of an AP and a STA such as an accesspoint (AP) 225 and a station (STA1) 200-1 which are successfullysynchronized to communicate with each other are not concepts indicatinga specific region. The BSS 205 may include one or more STAs 205-1 and205-2 which may be joined to one AP 230.

The BSS may include at least one STA, APs providing a distributionservice, and a distribution system (DS) 210 connecting multiple APs.

The distribution system 210 may implement an extended service set (ESS)240 extended by connecting the multiple BSSs 200 and 205. The ESS 240may be used as a term indicating one network configured by connectingone or more APs 225 or 230 through the distribution system 210. The APincluded in one ESS 240 may have the same service set identification(SSID).

A portal 220 may serve as a bridge which connects the wireless LANnetwork (IEEE 802.11) and another network (e.g., 802.X).

In the BSS illustrated in the upper part of FIG. 2 , a network betweenthe APs 225 and 230 and a network between the APs 225 and 230 and theSTAs 200-1, 205-1, and 205-2 may be implemented. However, the network isconfigured even between the STAs without the APs 225 and 230 to performcommunication. A network in which the communication is performed byconfiguring the network even between the STAs without the APs 225 and230 is defined as an Ad-Hoc network or an independent basic service set(IBSS).

A lower part of FIG. 2 illustrates a conceptual view illustrating theIBSS.

Referring to the lower part of FIG. 2 , the IBSS is a BSS that operatesin an Ad-Hoc mode. Since the IBSS does not include the access point(AP), a centralized management entity that performs a managementfunction at the center does not exist. That is, in the IBSS, STAs 250-1,250-2, 250-3, 255-4, and 255-5 are managed by a distributed manner. Inthe IBSS, all STAs 250-1, 250-2, 250-3, 255-4, and 255-5 may beconstituted by movable STAs and are not permitted to access the DS toconstitute a self-contained network.

FIG. 3 illustrates a general link setup process.

In S310, a STA may perform a network discovery operation. The networkdiscovery operation may include a scanning operation of the STA. Thatis, to access a network, the STA needs to discover a participatingnetwork. The STA needs to identify a compatible network beforeparticipating in a wireless network, and a process of identifying anetwork present in a particular area is referred to as scanning.Scanning methods include active scanning and passive scanning.

FIG. 3 illustrates a network discovery operation including an activescanning process. In active scanning, a STA performing scanningtransmits a probe request frame and waits for a response to the proberequest frame in order to identify which AP is present around whilemoving to channels. A responder transmits a probe response frame as aresponse to the probe request frame to the STA having transmitted theprobe request frame. Here, the responder may be a STA that transmits thelast beacon frame in a BSS of a channel being scanned. In the BSS, sincean AP transmits a beacon frame, the AP is the responder. In an IBSS,since STAs in the IBSS transmit a beacon frame in turns, the responderis not fixed. For example, when the STA transmits a probe request framevia channel 1 and receives a probe response frame via channel 1, the STAmay store BSS-related information included in the received proberesponse frame, may move to the next channel (e.g., channel 2), and mayperform scanning (e.g., transmits a probe request and receives a proberesponse via channel 2) by the same method.

Although not shown in FIG. 3 , scanning may be performed by a passivescanning method. In passive scanning, a STA performing scanning may waitfor a beacon frame while moving to channels. A beacon frame is one ofmanagement frames in IEEE 802.11 and is periodically transmitted toindicate the presence of a wireless network and to enable the STAperforming scanning to find the wireless network and to participate inthe wireless network. In a BSS, an AP serves to periodically transmit abeacon frame. In an IBSS, STAs in the IBSS transmit a beacon frame inturns. Upon receiving the beacon frame, the STA performing scanningstores information related to a BSS included in the beacon frame andrecords beacon frame information in each channel while moving to anotherchannel. The STA having received the beacon frame may store BSS-relatedinformation included in the received beacon frame, may move to the nextchannel, and may perform scanning in the next channel by the samemethod.

After discovering the network, the STA may perform an authenticationprocess in S320. The authentication process may be referred to as afirst authentication process to be clearly distinguished from thefollowing security setup operation in S340. The authentication processin S320 may include a process in which the STA transmits anauthentication request frame to the AP and the AP transmits anauthentication response frame to the STA in response. The authenticationframes used for an authentication request/response are managementframes.

The authentication frames may include information related to anauthentication algorithm number, an authentication transaction sequencenumber, a status code, a challenge text, a robust security network(RSN), and a finite cyclic group.

The STA may transmit the authentication request frame to the AP. The APmay determine whether to allow the authentication of the STA based onthe information included in the received authentication request frame.The AP may provide the authentication processing result to the STA viathe authentication response frame.

When the STA is successfully authenticated, the STA may perform anassociation process in S330. The association process includes a processin which the STA transmits an association request frame to the AP andthe AP transmits an association response frame to the STA in response.The association request frame may include, for example, informationrelated to various capabilities, a beacon listen interval, a service setidentifier (SSID), a supported rate, a supported channel, RSN, amobility domain, a supported operating class, a traffic indication map(TIM) broadcast request, and an interworking service capability. Theassociation response frame may include, for example, information relatedto various capabilities, a status code, an association ID (AID), asupported rate, an enhanced distributed channel access (EDCA) parameterset, a received channel power indicator (RCPI), a receivedsignal-to-noise indicator (RSNI), a mobility domain, a timeout interval(association comeback time), an overlapping BSS scanning parameter, aTIM broadcast response, and a QoS map.

In S340, the STA may perform a security setup process. The securitysetup process in S340 may include a process of setting up a private keythrough four-way handshaking, for example, through an extensibleauthentication protocol over LAN (EAPOL) frame.

FIG. 4 illustrates an example of a PPDU used in an IEEE standard.

As illustrated, various types of PHY protocol data units (PPDUs) areused in IEEE a/g/n/ac standards. Specifically, an LTF and a STF includea training signal, a SIG-A and a SIG-B include control information for areceiving STA, and a data field includes user data corresponding to aPSDU (MAC PDU/aggregated MAC PDU).

FIG. 4 also includes an example of an HE PPDU according to IEEE802.11ax. The HE PPDU according to FIG. 4 is an illustrative PPDU formultiple users. An HE-SIG-B may be included only in a PPDU for multipleusers, and an HE-SIG-B may be omitted in a PPDU for a single user.

As illustrated in FIG. 4 , the HE-PPDU for multiple users (MUs) mayinclude a legacy-short training field (L-STF), a legacy-long trainingfield (L-LTF), a legacy-signal (L-SIG), a high efficiency-signal A(HE-SIG A), a high efficiency-signal-B (HE-SIG B), a highefficiency-short training field (HE-STF), a high efficiency-longtraining field (HE-LTF), a data field (alternatively, an MAC payload),and a packet extension (PE) field. The respective fields may betransmitted for illustrated time periods (i.e., 4 or 8 μs).

Hereinafter, a resource unit (RU) used for a PPDU is described. An RUmay include a plurality of subcarriers (or tones). An RU may be used totransmit a signal to a plurality of STAs according to OFDMA. Further, anRU may also be defined to transmit a signal to one STA. An RU may beused for an STF, an LTF, a data field, or the like.

FIG. 5 illustrates a layout of resource units (RUs) used in a band of 20MHz.

As illustrated in FIG. 5 , resource units (RUs) corresponding todifferent numbers of tones (i.e., subcarriers) may be used to form somefields of an HE-PPDU. For example, resources may be allocated inillustrated RUs for an HE-STF, an HE-LTF, and a data field.

As illustrated in the uppermost part of FIG. 5 , a 26-unit (i.e., a unitcorresponding to 26 tones) may be disposed. Six tones may be used for aguard band in the leftmost band of the 20 MHz band, and five tones maybe used for a guard band in the rightmost band of the 20 MHz band.Further, seven DC tones may be inserted in a center band, that is, a DCband, and a 26-unit corresponding to 13 tones on each of the left andright sides of the DC band may be disposed. A 26-unit, a 52-unit, and a106-unit may be allocated to other bands. Each unit may be allocated fora receiving STA, that is, a user.

The layout of the RUs in FIG. 5 may be used not only for a multipleusers (MUs) but also for a single user (SU), in which case one 242-unitmay be used and three DC tones may be inserted as illustrated in thelowermost part of FIG. 5 .

Although FIG. 5 proposes RUs having various sizes, that is, a 26-RU, a52-RU, a 106-RU, and a 242-RU, specific sizes of RUs may be extended orincreased. Therefore, the present embodiment is not limited to thespecific size of each RU (i.e., the number of corresponding tones).

FIG. 6 illustrates a layout of RUs used in a band of 40 MHz.

Similarly to FIG. 5 in which RUs having various sizes are used, a 26-RU,a 52-RU, a 106-RU, a 242-RU, a 484-RU, and the like may be used in anexample of FIG. 6 . Further, five DC tones may be inserted in a centerfrequency, 12 tones may be used for a guard band in the leftmost band ofthe 40 MHz band, and 11 tones may be used for a guard band in therightmost band of the 40 MHz band.

As illustrated in FIG. 6 , when the layout of the RUs is used for asingle user, a 484-RU may be used. The specific number of RUs may bechanged similarly to FIG. 5 .

FIG. 7 illustrates a layout of RUs used in a band of 80 MHz.

Similarly to FIG. 5 and FIG. 6 in which RUs having various sizes areused, a 26-RU, a 52-RU, a 106-RU, a 242-RU, a 484-RU, a 996-RU, and thelike may be used in an example of FIG. 7 . Further, seven DC tones maybe inserted in the center frequency, 12 tones may be used for a guardband in the leftmost band of the 80 MHz band, and 11 tones may be usedfor a guard band in the rightmost band of the 80 MHz band. In addition,a 26-RU corresponding to 13 tones on each of the left and right sides ofthe DC band may be used.

As illustrated in FIG. 7 , when the layout of the RUs is used for asingle user, a 996-RU may be used, in which case five DC tones may beinserted.

The RU described in the present specification may be used in uplink (UL)communication and downlink (DL) communication. For example, when UL-MUcommunication which is solicited by a trigger frame is performed, atransmitting STA (e.g., an AP) may allocate a first RU (e.g.,26/52/106/242-RU, etc.) to a first STA through the trigger frame, andmay allocate a second RU (e.g., 26/52/106/242-RU, etc.) to a second STA.Thereafter, the first STA may transmit a first trigger-based PPDU basedon the first RU, and the second STA may transmit a second trigger-basedPPDU based on the second RU. The first/second trigger-based PPDU istransmitted to the AP at the same (or overlapped) time period.

For example, when a DL MU PPDU is configured, the transmitting STA(e.g., AP) may allocate the first RU (e.g., 26/52/106/242-RU, etc.) tothe first STA, and may allocate the second RU (e.g., 26/52/106/242-RU,etc.) to the second STA. That is, the transmitting STA (e.g., AP) maytransmit HE-STF, HE-LTF, and Data fields for the first STA through thefirst RU in one MU PPDU, and may transmit HE-STF, HE-LTF, and Datafields for the second STA through the second RU.

Information related to a layout of the RU may be signaled throughHE-SIG-B.

FIG. 8 illustrates a structure of an HE-SIG-B field.

As illustrated, an HE-SIG-B field 810 includes a common field 820 and auser-specific field 830. The common field 820 may include informationcommonly applied to all users (i.e., user STAs) which receive SIG-B. Theuser-specific field 830 may be called a user-specific control field.When the SIG-B is transferred to a plurality of users, the user-specificfield 830 may be applied only any one of the plurality of users.

As illustrated in FIG. 8 , the common field 820 and the user-specificfield 830 may be separately encoded.

The common field 820 may include RU allocation information of N*8 bits.For example, the RU allocation information may include informationrelated to a location of an RU. For example, when a 20 MHz channel isused as shown in FIG. 5 , the RU allocation information may includeinformation related to a specific frequency band to which a specific RU(26-RU/52-RU/106-RU) is arranged.

An example of a case in which the RU allocation information consists of8 bits is as follows.

TABLE 1 8 bits indices Number (B7 B6 B5 B4 of B3 B2 B1 B0) #1 #2 #3 #4#5 #6 #7 #8 #9 entries 00000000 26 26 26 26 26 26 26 26 26 1 00000001 2626 26 26 26 26 26 52 1 00000010 26 26 26 26 26 52 26 26 1 00000011 26 2626 26 26 52 52 1 00000100 26 26 52 26 26 26 26 26 1 00000101 26 26 52 2626 26 52 1 00000110 26 26 52 26 52 26 26 1 00000111 26 26 52 26 52 52 100001000 52 26 26 26 26 26 26 26 1

As shown the example of FIG. 5 , up to nine 26-RUs may be allocated tothe 20 MHz channel. When the RU allocation information of the commonfield 820 is set to “00000000” as shown in Table 1, the nine 26-RUs maybe allocated to a corresponding channel (i.e., 20 MHz). In addition,when the RU allocation information of the common field 820 is set to“00000001” as shown in Table 1, seven 26-RUs and one 52-RU are arrangedin a corresponding channel. That is, in the example of FIG. 5 , the52-RU may be allocated to the rightmost side, and the seven 26-RUs maybe allocated to the left thereof.

The example of Table 1 shows only some of RU locations capable ofdisplaying the RU allocation information.

For example, the RU allocation information may include an example ofTable 2 below.

TABLE 2 8 bits indices Number (B7 B6 B5 B4 of 83 B2 B1 B0) #1 #2 #3 #4#5 #6 #7 #8 #9 entries 01000y₂y₁y₀ 106 26 26 26 26 26 8 01001y₂y₁y₀ 10626 26 26 52 8

“01000y2y1y0” relates to an example in which a 106-RU is allocated tothe leftmost side of the 20 MHz channel, and five 26-RUs are allocatedto the right side thereof. In this case, a plurality of STAs (e.g.,user-STAs) may be allocated to the 106-RU, based on a MU-MIMO scheme.Specifically, up to 8 STAs (e.g., user-STAs) may be allocated to the106-RU, and the number of STAs (e.g., user-STAs) allocated to the 106-RUis determined based on 3-bit information (y2y1y0). For example, when the3-bit information (y2y1y0) is set to N, the number of STAs (e.g.,user-STAs) allocated to the 106-RU based on the MU-MIMO scheme may beN+1.

In general, a plurality of STAs (e.g., user STAs) different from eachother may be allocated to a plurality of RUs. However, the plurality ofSTAs (e.g., user STAs) may be allocated to one or more RUs having atleast a specific size (e.g., 106 subcarriers), based on the MU-MIMOscheme.

As shown in FIG. 8 , the user-specific field 830 may include a pluralityof user fields. As described above, the number of STAs (e.g., user STAs)allocated to a specific channel may be determined based on the RUallocation information of the common field 820. For example, when the RUallocation information of the common field 820 is “00000000”, one userSTA may be allocated to each of nine 26-RUs (e.g., nine user STAs may beallocated). That is, up to 9 user STAs may be allocated to a specificchannel through an OFDMA scheme. In other words, up to 9 user STAs maybe allocated to a specific channel through a non-MU-MIMO scheme.

For example, when RU allocation is set to “01000y2y1y0”, a plurality ofSTAs may be allocated to the 106-RU arranged at the leftmost sidethrough the MU-MIMO scheme, and five user STAs may be allocated to five26-RUs arranged to the right side thereof through the non-MU MIMOscheme. This case is specified through an example of FIG. 9 .

FIG. 9 illustrates an example in which a plurality of user STAs areallocated to the same RU through a MU-MIMO scheme.

For example, when RU allocation is set to “01000010” as shown in FIG. 9, a 106-RU may be allocated to the leftmost side of a specific channel,and five 26-RUs may be allocated to the right side thereof. In addition,three user STAs may be allocated to the 106-RU through the MU-MIMOscheme. As a result, since eight user STAs are allocated, theuser-specific field 830 of HE-SIG-B may include eight user fields.

The eight user fields may be expressed in the order shown in FIG. 9 . Inaddition, as shown in FIG. 8 , two user fields may be implemented withone user block field.

The user fields shown in FIG. 8 and FIG. 9 may be configured based ontwo formats. That is, a user field related to a MU-MIMO scheme may beconfigured in a first format, and a user field related to a non-MIMOscheme may be configured in a second format. Referring to the example ofFIG. 9 , a user field 1 to a user field 3 may be based on the firstformat, and a user field 4 to a user field 8 may be based on the secondformat. The first format or the second format may include bitinformation of the same length (e.g., 21 bits).

Each user field may have the same size (e.g., 21 bits). For example, theuser field of the first format (the first of the MU-MIMO scheme) may beconfigured as follows.

For example, a first bit (i.e., B0-B10) in the user field (i.e., 21bits) may include identification information (e.g., STA-ID, partial AID,etc.) of a user STA to which a corresponding user field is allocated. Inaddition, a second bit (i.e., B11-B14) in the user field (i.e., 21 bits)may include information related to a spatial configuration.Specifically, an example of the second bit (i.e., B11-B14) may be asshown in Table 3 and Table 4 below.

TABLE 3 Number N_(STS) N_(STS) N_(STS) N_(STS) N_(STS) N_(STS) N_(STS)N_(STS) Total of N_(user) B3 . . . B0 [1] [2] [3] [4] [5] [6] [7] [8]N_(STS) entries 2 0000-0011 1-4 1 z z z z 2-5 10 0100-0110 2-4 2 4-60111-1000 3-4 3 6-7 1001 4 4 8 3 0000-0011 1-4 1 1 3-6 13 0100-0110 2-42 1 5-7 0111-1000 3-4 3 1 7-8 1001-1011 2-4 2 2 6-8 1100 3 3 2 8 40000-0011 1-4 1 1 1 4-7 11 0100-0110 2-4 2 1 1 6-8 0111 3 3 1 1 81000-1001 2-3 2 2 1 7-8 1010 2 2 2 2 8

TABLE 4 Number N_(STS) N_(STS) N_(STS) N_(STS) N_(STS) N_(STS) N_(STS)N_(STS) Total of N_(user) B3 . . . B0 [1] [2] [3] [4] [5] [6] [7] [8]N_(STS) entries 5 0000-0011 1-4 1 1 1 1 5-8 7 0100-0101 2-3 2 1 1 1 7-80110 2 2 2 1 1 8 6 0000-0010 1-3 1 1 1 1 1 6-8 4 0011 2 2 1 1 1 1 8 70000-0001 1-2 1 1 1 1 1 1 7-8 2 8 0000 1 1 1 1 1 1 1 1 8 1

As shown in Table 3 and/or Table 4, the second bit (e.g., B11-B14) mayinclude information related to the number of spatial streams allocatedto the plurality of user STAs which are allocated based on the MU-MIMOscheme. For example, when three user STAs are allocated to the 106-RUbased on the MU-MIMO scheme as shown in FIG. 9 , N_user is set to “3”.Therefore, values of N_STS[1], N_STS[2], and N_STS[3] may be determinedas shown in Table 3. For example, when a value of the second bit(B11-B14) is “0011”, it may be set to N_STS[1]=4, N_STS[2]=1,N_STS[3]=1. That is, in the example of FIG. 9 , four spatial streams maybe allocated to the user field 1, one spatial stream may be allocated tothe user field 1, and one spatial stream may be allocated to the userfield 3.

As shown in the example of Table 3 and/or Table 4, information (i.e.,the second bit, B11-B14) related to the number of spatial streams forthe user STA may consist of 4 bits. In addition, the information (i.e.,the second bit, B11-B14) on the number of spatial streams for the userSTA may support up to eight spatial streams. In addition, theinformation (i.e., the second bit, B11-B14) on the number of spatialstreams for the user STA may support up to four spatial streams for oneuser STA.

In addition, a third bit (i.e., B15-18) in the user field (i.e., 21bits) may include modulation and coding scheme (MCS) information. TheMCS information may be applied to a data field in a PPDU includingcorresponding SIG-B.

An MCS, MCS information, an MCS index, an MCS field, or the like used inthe present specification may be indicated by an index value. Forexample, the MCS information may be indicated by an index 0 to an index11. The MCS information may include information related to aconstellation modulation type (e.g., BPSK, QPSK, 16-QAM, 64-QAM,256-QAM, 1024-QAM, etc.) and information related to a coding rate (e.g.,1/2, 2/3, 3/4, 5/6e, etc.). Information related to a channel coding type(e.g., LCC or LDPC) may be excluded in the MCS information.

In addition, a fourth bit (i.e., B19) in the user field (i.e., 21 bits)may be a reserved field.

In addition, a fifth bit (i.e., B20) in the user field (i.e., 21 bits)may include information related to a coding type (e.g., BCC or LDPC).That is, the fifth bit (i.e., B20) may include information related to atype (e.g., BCC or LDPC) of channel coding applied to the data field inthe PPDU including the corresponding SIG-B.

The aforementioned example relates to the user field of the first format(the format of the MU-MIMO scheme). An example of the user field of thesecond format (the format of the non-MU-MIMO scheme) is as follows.

A first bit (e.g., B0-B10) in the user field of the second format mayinclude identification information of a user STA. In addition, a secondbit (e.g., B11-B13) in the user field of the second format may includeinformation related to the number of spatial streams applied to acorresponding RU. In addition, a third bit (e.g., B14) in the user fieldof the second format may include information related to whether abeamforming steering matrix is applied. A fourth bit (e.g., B15-B18) inthe user field of the second format may include modulation and codingscheme (MCS) information. In addition, a fifth bit (e.g., B19) in theuser field of the second format may include information related towhether dual carrier modulation (DCM) is applied. In addition, a sixthbit (i.e., B20) in the user field of the second format may includeinformation related to a coding type (e.g., BCC or LDPC).

FIG. 10 illustrates an operation based on UL-MU. As illustrated, atransmitting STA (e.g., an AP) may perform channel access throughcontending (e.g., a backoff operation), and may transmit a trigger frame1030. That is, the transmitting STA may transmit a PPDU including thetrigger frame 1030. Upon receiving the PPDU including the trigger frame,a trigger-based (TB) PPDU is transmitted after a delay corresponding toSIFS.

TB PPDUs 1041 and 1042 may be transmitted at the same time period, andmay be transmitted from a plurality of STAs (e.g., user STAs) havingAIDs indicated in the trigger frame 1030. An ACK frame 1050 for the TBPPDU may be implemented in various forms.

A specific feature of the trigger frame is described with reference toFIG. 11 to FIG. 13 . Even if UL-MU communication is used, an orthogonalfrequency division multiple access (OFDMA) scheme or a MU MIMO schememay be used, and the OFDMA and MU-MIMO schemes may be simultaneouslyused.

FIG. 11 illustrates an example of a trigger frame. The trigger frame ofFIG. 11 allocates a resource for uplink multiple-user (MU) transmission,and may be transmitted, for example, from an AP. The trigger frame maybe configured of a MAC frame, and may be included in a PPDU.

Each field shown in FIG. 11 may be partially omitted, and another fieldmay be added. In addition, a length of each field may be changed to bedifferent from that shown in the figure.

A frame control field 1110 of FIG. 11 may include information related toa MAC protocol version and extra additional control information. Aduration field 1120 may include time information for NAV configurationor information related to an identifier (e.g., AID) of a STA.

In addition, an RA field 1130 may include address information of areceiving STA of a corresponding trigger frame, and may be optionallyomitted. A TA field 1140 may include address information of a STA (e.g.,an AP) which transmits the corresponding trigger frame. A commoninformation field 1150 includes common control information applied tothe receiving STA which receives the corresponding trigger frame. Forexample, a field indicating a length of an L-SIG field of an uplink PPDUtransmitted in response to the corresponding trigger frame orinformation for controlling content of a SIG-A field (i.e., HE-SIG-Afield) of the uplink PPDU transmitted in response to the correspondingtrigger frame may be included. In addition, as common controlinformation, information related to a length of a CP of the uplink PPDUtransmitted in response to the corresponding trigger frame orinformation related to a length of an LTF field may be included.

In addition, per user information fields 1160 #1 to 1160 #Ncorresponding to the number of receiving STAs which receive the triggerframe of FIG. 11 are preferably included. The per user information fieldmay also be called an “allocation field”.

In addition, the trigger frame of FIG. 11 may include a padding field1170 and a frame check sequence field 1180.

Each of the per user information fields 1160 #1 to 1160 #N shown in FIG.11 may include a plurality of subfields.

FIG. 12 illustrates an example of a common information field of atrigger frame. A subfield of FIG. 12 may be partially omitted, and anextra subfield may be added. In addition, a length of each subfieldillustrated may be changed.

A length field 1210 illustrated has the same value as a length field ofan L-SIG field of an uplink PPDU transmitted in response to acorresponding trigger frame, and a length field of the L-SIG field ofthe uplink PPDU indicates a length of the uplink PPDU. As a result, thelength field 1210 of the trigger frame may be used to indicate thelength of the corresponding uplink PPDU.

In addition, a cascade identifier field 1220 indicates whether a cascadeoperation is performed. The cascade operation implies that downlink MUtransmission and uplink MU transmission are performed together in thesame TXOP. That is, it implies that downlink MU transmission isperformed and thereafter uplink MU transmission is performed after apre-set time (e.g., SIFS). During the cascade operation, only onetransmitting device (e.g., AP) may perform downlink communication, and aplurality of transmitting devices (e.g., non-APs) may perform uplinkcommunication.

A CS request field 1230 indicates whether a wireless medium state or aNAV or the like is necessarily considered in a situation where areceiving device which has received a corresponding trigger frametransmits a corresponding uplink PPDU.

An HE-SIG-A information field 1240 may include information forcontrolling content of a SIG-A field (i.e., HE-SIG-A field) of theuplink PPDU in response to the corresponding trigger frame.

A CP and LTF type field 1250 may include information related to a CPlength and LTF length of the uplink PPDU transmitted in response to thecorresponding trigger frame. A trigger type field 1260 may indicate apurpose of using the corresponding trigger frame, for example, typicaltriggering, triggering for beamforming, a request for block ACK/NACK, orthe like.

It may be assumed that the trigger type field 1260 of the trigger framein the present specification indicates a trigger frame of a basic typefor typical triggering. For example, the trigger frame of the basic typemay be referred to as a basic trigger frame.

FIG. 13 illustrates an example of a subfield included in a per userinformation field. A user information field 1300 of FIG. 13 may beunderstood as any one of the per user information fields 1160 #1 to 1160#N mentioned above with reference to FIG. 11 . A subfield included inthe user information field 1300 of FIG. 13 may be partially omitted, andan extra subfield may be added. In addition, a length of each subfieldillustrated may be changed.

A user identifier field 1310 of FIG. 13 indicates an identifier of a STA(i.e., receiving STA) corresponding to per user information. An exampleof the identifier may be the entirety or part of an associationidentifier (AID) value of the receiving STA.

In addition, an RU allocation field 1320 may be included. That is, whenthe receiving STA identified through the user identifier field 1310transmits a TB PPDU in response to the trigger frame, the TB PPDU istransmitted through an RU indicated by the RU allocation field 1320. Inthis case, the RU indicated by the RU allocation field 1320 may be an RUshown in FIG. 5 , FIG. 6 , and FIG. 7 .

The subfield of FIG. 13 may include a coding type field 1330. The codingtype field 1330 may indicate a coding type of the TB PPDU. For example,when BCC coding is applied to the TB PPDU, the coding type field 1330may be set to ‘1’, and when LDPC coding is applied, the coding typefield 1330 may be set to ‘0’.

In addition, the subfield of FIG. 13 may include an MCS field 1340. TheMCS field 1340 may indicate an MCS scheme applied to the TB PPDU. Forexample, when BCC coding is applied to the TB PPDU, the coding typefield 1330 may be set to ‘1’, and when LDPC coding is applied, thecoding type field 1330 may be set to ‘0’.

Hereinafter, a UL OFDMA-based random access (UORA) scheme will bedescribed.

FIG. 14 describes a technical feature of the UORA scheme.

A transmitting STA (e.g., an AP) may allocate six RU resources through atrigger frame as shown in FIG. 14 . Specifically, the AP may allocate a1st RU resource (AID 0, RU 1), a 2nd RU resource (AID 0, RU 2), a 3rd RUresource (AID 0, RU 3), a 4th RU resource (AID 2045, RU 4), a 5th RUresource (AID 2045, RU 5), and a 6th RU resource (AID 3, RU 6).Information related to the AID 0, AID 3, or AID 2045 may be included,for example, in the user identifier field 1310 of FIG. 13 . Informationrelated to the RU 1 to RU 6 may be included, for example, in the RUallocation field 1320 of FIG. 13 . AID=0 may imply a UORA resource foran associated STA, and AID=2045 may imply a UORA resource for anun-associated STA. Accordingly, the 1st to 3rd RU resources of FIG. 14may be used as a UORA resource for the associated STA, the 4th and 5thRU resources of FIG. 14 may be used as a UORA resource for theun-associated STA, and the 6th RU resource of FIG. 14 may be used as atypical resource for UL MU.

In the example of FIG. 14 , an OFDMA random access backoff (OBO) of aSTA1 is decreased to 0, and the STA1 randomly selects the 2nd RUresource (AID 0, RU 2). In addition, since an OBO counter of a STA2/3 isgreater than 0, an uplink resource is not allocated to the STA2/3. Inaddition, regarding a STA4 in FIG. 14 , since an AID (e.g., AID=3) ofthe STA4 is included in a trigger frame, a resource of the RU 6 isallocated without backoff.

Specifically, since the STA1 of FIG. 14 is an associated STA, the totalnumber of eligible RA RUs for the STA1 is 3 (RU 1, RU 2, and RU 3), andthus the STA1 decreases an OBO counter by 3 so that the OBO counterbecomes 0. In addition, since the STA2 of FIG. 14 is an associated STA,the total number of eligible RA RUs for the STA2 is 3 (RU 1, RU 2, andRU 3), and thus the STA2 decreases the OBO counter by 3 but the OBOcounter is greater than 0. In addition, since the STA3 of FIG. 14 is anun-associated STA, the total number of eligible RA RUs for the STA3 is 2(RU 4, RU 5), and thus the STA3 decreases the OBO counter by 2 but theOBO counter is greater than 0.

FIG. 15 illustrates an example of a channel used/supported/definedwithin a 2.4 GHz band.

The 2.4 GHz band may be called in other terms such as a first band. Inaddition, the 2.4 GHz band may imply a frequency domain in whichchannels of which a center frequency is close to 2.4 GHz (e.g., channelsof which a center frequency is located within 2.4 to 2.5 GHz) areused/supported/defined.

A plurality of 20 MHz channels may be included in the 2.4 GHz band. 20MHz within the 2.4 GHz may have a plurality of channel indices (e.g., anindex 1 to an index 14). For example, a center frequency of a 20 MHzchannel to which a channel index 1 is allocated may be 2.412 GHz, acenter frequency of a 20 MHz channel to which a channel index 2 isallocated may be 2.417 GHz, and a center frequency of a 20 MHz channelto which a channel index N is allocated may be (2.407+0.005*N) GHz. Thechannel index may be called in various terms such as a channel number orthe like. Specific numerical values of the channel index and centerfrequency may be changed.

FIG. 15 exemplifies 4 channels within a 2.4 GHz band. Each of 1st to 4thfrequency domains 1510 to 1540 shown herein may include one channel. Forexample, the 1st frequency domain 1510 may include a channel 1 (a 20 MHzchannel having an index 1). In this case, a center frequency of thechannel 1 may be set to 2412 MHz. The 2nd frequency domain 1520 mayinclude a channel 6. In this case, a center frequency of the channel 6may be set to 2437 MHz. The 3rd frequency domain 1530 may include achannel 11. In this case, a center frequency of the channel 11 may beset to 2462 MHz. The 4th frequency domain 1540 may include a channel 14.In this case, a center frequency of the channel 14 may be set to 2484MHz.

FIG. 16 illustrates an example of a channel used/supported/definedwithin a 5 GHz band.

The 5 GHz band may be called in other terms such as a second band or thelike. The 5 GHz band may imply a frequency domain in which channels ofwhich a center frequency is greater than or equal to 5 GHz and less than6 GHz (or less than 5.9 GHz) are used/supported/defined. Alternatively,the 5 GHz band may include a plurality of channels between 4.5 GHz and5.5 GHz. A specific numerical value shown in FIG. 16 may be changed.

A plurality of channels within the 5 GHz band include an unlicensednational information infrastructure (UNII)-1, a UNII-2, a UNII-3, and anISM. The INII-1 may be called UNII Low. The UNII-2 may include afrequency domain called UNII Mid and UNII-2Extended.

The UNII-3 may be called UNII-Upper.

A plurality of channels may be configured within the 5 GHz band, and abandwidth of each channel may be variously set to, for example, 20 MHz,40 MHz, 80 MHz, 160 MHz, or the like. For example, 5170 MHz to 5330 MHzfrequency domains/ranges within the UNII-1 and UNII-2 may be dividedinto eight 20 MHz channels. The 5170 MHz to 5330 MHz frequencydomains/ranges may be divided into four channels through a 40 MHzfrequency domain. The 5170 MHz to 5330 MHz frequency domains/ranges maybe divided into two channels through an 80 MHz frequency domain.Alternatively, the 5170 MHz to 5330 MHz frequency domains/ranges may bedivided into one channel through a 160 MHz frequency domain.

FIG. 17 illustrates an example of a channel used/supported/definedwithin a 6 GHz band.

The 6 GHz band may be called in other terms such as a third band or thelike. The 6 GHz band may imply a frequency domain in which channels ofwhich a center frequency is greater than or equal to 5.9 GHz areused/supported/defined. A specific numerical value shown in FIG. 17 maybe changed.

For example, the 20 MHz channel of FIG. 17 may be defined starting from5.940 GHz. Specifically, among 20 MHz channels of FIG. 17 , the leftmostchannel may have an index 1 (or a channel index, a channel number,etc.), and 5.945 GHz may be assigned as a center frequency. That is, acenter frequency of a channel of an index N may be determined as(5.940+0.005*N) GHz.

Accordingly, an index (or channel number) of the 2 MHz channel of FIG.17 may be 1, 5, 9, 13, 17, 21, 25, 29, 33, 37, 41, 45, 49, 53, 57, 61,65, 69, 73, 77, 81, 85, 89, 93, 97, 101, 105, 109, 113, 117, 121, 125,129, 133, 137, 141, 145, 149, 153, 157, 161, 165, 169, 173, 177, 181,185, 189, 193, 197, 201, 205, 209, 213, 217, 221, 225, 229, 233. Inaddition, according to the aforementioned (5.940+0.005*N)GHz rule, anindex of the 40 MHz channel of FIG. 17 may be 3, 11, 19, 27, 35, 43, 51,59, 67, 75, 83, 91, 99, 107, 115, 123, 131, 139, 147, 155, 163, 171,179, 187, 195, 203, 211, 219, 227.

Although 20, 40, 80, and 160 MHz channels are illustrated in the exampleof FIG. 17 , a 240 MHz channel or a 320 MHz channel may be additionallyadded.

Hereinafter, a PPDU transmitted/received in a STA of the presentspecification will be described.

FIG. 18 illustrates an example of a PPDU used in the presentspecification.

The PPDU of FIG. 18 may be called in various terms such as an EHT PPDU,a TX PPDU, an RX PPDU, a first type or N-th type PPDU, or the like. Forexample, in the present specification, the PPDU or the EHT PPDU may becalled in various terms such as a TX PPDU, a RX PPDU, a first type orN-th type PPDU, or the like. In addition, the EHT PPDU may be used in anEHT system and/or a new WLAN system enhanced from the EHT system.

The PPDU of FIG. 18 may indicate the entirety or part of a PPDU typeused in the EHT system. For example, the example of FIG. 18 may be usedfor both of a single-user (SU) mode and a multi-user (MU) mode. In otherwords, the PPDU of FIG. 18 may be a PPDU for one receiving STA or aplurality of receiving STAs. When the PPDU of FIG. 18 is used for atrigger-based (TB) mode, the EHT-SIG of FIG. 18 may be omitted. In otherwords, a STA which has received a trigger frame for uplink-MU (UL-MU)may transmit the PPDU in which the EHT-SIG is omitted in the example ofFIG. 18 .

In FIG. 18 , an L-STF to an EHT-LTF may be called a preamble or aphysical preamble, and may begenerated/transmitted/received/obtained/decoded in a physical layer.

A subcarrier spacing of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, andEHT-SIG fields of FIG. 18 may be determined as 312.5 kHz, and asubcarrier spacing of the EHT-STF, EHT-LTF, and Data fields may bedetermined as 78.125 kHz. That is, a tone index (or subcarrier index) ofthe L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG fields may beexpressed in unit of 312.5 kHz, and a tone index (or subcarrier index)of the EHT-STF, EHT-LTF, and Data fields may be expressed in unit of78.125 kHz.

In the PPDU of FIG. 18 , the L-LTE and the L-STF may be the same asthose in the conventional fields.

The L-SIG field of FIG. 18 may include, for example, bit information of24 bits. For example, the 24-bit information may include a rate field of4 bits, a reserved bit of 1 bit, a length field of 12 bits, a parity bitof 1 bit, and a tail bit of 6 bits. For example, the length field of 12bits may include information related to a length or time duration of aPPDU. For example, the length field of 12 bits may be determined basedon a type of the PPDU. For example, when the PPDU is a non-HT, HT, VHTPPDU or an EHT PPDU, a value of the length field may be determined as amultiple of 3. For example, when the PPDU is an HE PPDU, the value ofthe length field may be determined as “a multiple of 3”+1 or “a multipleof 3”+2. In other words, for the non-HT, HT, VHT PPDI or the EHT PPDU,the value of the length field may be determined as a multiple of 3, andfor the HE PPDU, the value of the length field may be determined as “amultiple of 3”+1 or “a multiple of 3”+2.

For example, the transmitting STA may apply BCC encoding based on a 1/2coding rate to the 24-bit information of the L-SIG field. Thereafter,the transmitting STA may obtain a BCC coding bit of 48 bits. BPSKmodulation may be applied to the 48-bit coding bit, thereby generating48 BPSK symbols. The transmitting STA may map the 48 BPSK symbols topositions except for a pilot subcarrier{subcarrier index −21, −7, +7,+21} and a DC subcarrier{subcarrier index 0}. As a result, the 48 BPSKsymbols may be mapped to subcarrier indices −26 to −22, −20 to −8, −6 to−1, +1 to +6, +8 to +20, and +22 to +26. The transmitting STA mayadditionally map a signal of {−1, −1, −1, 1} to a subcarrier index{−28,−27, +27, +28}. The aforementioned signal may be used for channelestimation on a frequency domain corresponding to {−28, −27, +27, +28}.

The transmitting STA may generate an RL-SIG generated in the same manneras the L-SIG. BPSK modulation may be applied to the RL-SIG. Thereceiving STA may know that the RX PPDU is the HE PPDU or the EHT PPDU,based on the presence of the RL-SIG.

A universal SIG (U-SIG) may be inserted after the RL-SIG of FIG. 18 .The U-SIB may be called in various terms such as a first SIG field, afirst SIG, a first type SIG, a control signal, a control signal field, afirst (type) control signal, or the like.

The U-SIG may include information of N bits, and may include informationfor identifying a type of the EHT PPDU. For example, the U-SIG may beconfigured based on two symbols (e.g., two contiguous OFDM symbols).Each symbol (e.g., OFDM symbol) for the U-SIG may have a duration of 4us. Each symbol of the U-SIG may be used to transmit the 26-bitinformation. For example, each symbol of the U-SIG may betransmitted/received based on 52 data tomes and 4 pilot tones.

Through the U-SIG (or U-SIG field), for example, A-bit information(e.g., 52 un-coded bits) may be transmitted. A first symbol of the U-SIGmay transmit first X-bit information (e.g., 26 un-coded bits) of theA-bit information, and a second symbol of the U-SIB may transmit theremaining Y-bit information (e.g., 26 un-coded bits) of the A-bitinformation. For example, the transmitting STA may obtain 26 un-codedbits included in each U-SIG symbol. The transmitting STA may performconvolutional encoding (i.e., BCC encoding) based on a rate of R=1/2 togenerate 52-coded bits, and may perform interleaving on the 52-codedbits. The transmitting STA may perform BPSK modulation on theinterleaved 52-coded bits to generate 52 BPSK symbols to be allocated toeach U-SIG symbol. One U-SIG symbol may be transmitted based on 65 tones(subcarriers) from a subcarrier index −28 to a subcarrier index +28,except for a DC index 0. The 52 BPSK symbols generated by thetransmitting STA may be transmitted based on the remaining tones(subcarriers) except for pilot tones, i.e., tones −21, −7, +7, +21.

For example, the A-bit information (e.g., 52 un-coded bits) generated bythe U-SIG may include a CRC field (e.g., a field having a length of 4bits) and a tail field (e.g., a field having a length of 6 bits). TheCRC field and the tail field may be transmitted through the secondsymbol of the U-SIG. The CRC field may be generated based on 26 bitsallocated to the first symbol of the U-SIG and the remaining 16 bitsexcept for the CRC/tail fields in the second symbol, and may begenerated based on the conventional CRC calculation algorithm. Inaddition, the tail field may be used to terminate trellis of aconvolutional decoder, and may be set to, for example, “000000”.

The A-bit information (e.g., 52 un-coded bits) transmitted by the U-SIG(or U-SIG field) may be divided into version-independent bits andversion-dependent bits. For example, the version-independent bits mayhave a fixed or variable size. For example, the version-independent bitsmay be allocated only to the first symbol of the U-SIG, or theversion-independent bits may be allocated to both of the first andsecond symbols of the U-SIG. For example, the version-independent bitsand the version-dependent bits may be called in various terms such as afirst control bit, a second control bit, or the like.

For example, the version-independent bits of the U-SIG may include a PHYversion identifier of 3 bits. For example, the PHY version identifier of3 bits may include information related to a PHY version of a TX/RX PPDU.For example, a first value of the PHY version identifier of 3 bits mayindicate that the TX/RX PPDU is an EHT PPDU. In other words, when thetransmitting STA transmits the EHT PPDU, the PHY version identifier of 3bits may be set to a first value. In other words, the receiving STA maydetermine that the RX PPDU is the EHT PPDU, based on the PHY versionidentifier having the first value.

For example, the version-independent bits of the U-SIG may include aUL/DL flag field of 1 bit. A first value of the UL/DL flag field of 1bit relates to UL communication, and a second value of the UL/DL flagfield relates to DL communication.

For example, the version-independent bits of the U-SIG may includeinformation related to a TXOP length and information related to a BSScolor ID.

For example, when the EHT PPDU is divided into various types (e.g.,various types such as an EHT PPDU related to an SU mode, an EHT PPDUrelated to a MU mode, an EHT PPDU related to a TB mode, an EHT PPDUrelated to extended range transmission, or the like), informationrelated to the type of the EHT PPDU may be included in theversion-dependent bits of the U-SIG.

For example, the U-SIG may include: 1) a bandwidth field includinginformation related to a bandwidth; 2) a field including informationrelated to an MCS scheme applied to EHT-SIG; 3) an indication fieldincluding information regarding whether a dual subcarrier modulation(DCM) scheme is applied to EHT-SIG; 4) a field including informationrelated to the number of symbol used for EHT-SIG; 5) a field includinginformation regarding whether the EHT-SIG is generated across a fullband; 6) a field including information related to a type of EHT-LTF/STF;and 7) information related to a field indicating an EHT-LTF length and aCP length.

Preamble puncturing may be applied to the PPDU of FIG. 18 . The preamblepuncturing implies that puncturing is applied to part (e.g., a secondary20 MHz band) of the full band. For example, when an 80 MHz PPDU istransmitted, a STA may apply puncturing to the secondary 20 MHz band outof the 80 MHz band, and may transmit a PPDU only through a primary 20MHz band and a secondary 40 MHz band.

For example, a pattern of the preamble puncturing may be configured inadvance. For example, when a first puncturing pattern is applied,puncturing may be applied only to the secondary 20 MHz band within the80 MHz band. For example, when a second puncturing pattern is applied,puncturing may be applied to only any one of two secondary 20 MHz bandsincluded in the secondary 40 MHz band within the 80 MHz band. Forexample, when a third puncturing pattern is applied, puncturing may beapplied to only the secondary 20 MHz band included in the primary 80 MHzband within the 160 MHz band (or 80+80 MHz band). For example, when afourth puncturing is applied, puncturing may be applied to at least one20 MHz channel not belonging to a primary 40 MHz band in the presence ofthe primary 40 MHz band included in the 80 MHz band within the 160 MHzband (or 80+80 MHz band).

Information related to the preamble puncturing applied to the PPDU maybe included in U-SIG and/or EHT-SIG. For example, a first field of theU-SIG may include information related to a contiguous bandwidth, andsecond field of the U-SIG may include information related to thepreamble puncturing applied to the PPDU.

For example, the U-SIG and the EHT-SIG may include the informationrelated to the preamble puncturing, based on the following method. Whena bandwidth of the PPDU exceeds 80 MHz, the U-SIG may be configuredindividually in unit of 80 MHz. For example, when the bandwidth of thePPDU is 160 MHz, the PPDU may include a first U-SIG for a first 80 MHzband and a second U-SIG for a second 80 MHz band. In this case, a firstfield of the first U-SIG may include information related to a 160 MHzbandwidth, and a second field of the first U-SIG may include informationrelated to a preamble puncturing (i.e., information related to apreamble puncturing pattern) applied to the first 80 MHz band. Inaddition, a first field of the second U-SIG may include informationrelated to a 160 MHz bandwidth, and a second field of the second U-SIGmay include information related to a preamble puncturing (i.e.,information related to a preamble puncturing pattern) applied to thesecond 80 MHz band. Meanwhile, an EHT-SIG contiguous to the first U-SIGmay include information related to a preamble puncturing applied to thesecond 80 MHz band (i.e., information related to a preamble puncturingpattern), and an EHT-SIG contiguous to the second U-SIG may includeinformation related to a preamble puncturing (i.e., information relatedto a preamble puncturing pattern) applied to the first 80 MHz band.

Additionally or alternatively, the U-SIG and the EHT-SIG may include theinformation related to the preamble puncturing, based on the followingmethod. The U-SIG may include information related to a preamblepuncturing (i.e., information related to a preamble puncturing pattern)for all bands. That is, the EHT-SIG may not include the informationrelated to the preamble puncturing, and only the U-SIG may include theinformation related to the preamble puncturing (i.e., the informationrelated to the preamble puncturing pattern).

The U-SIG may be configured in unit of 20 MHz. For example, when an 80MHz PPDU is configured, the U-SIG may be duplicated. That is, fouridentical U-SIGs may be included in the 80 MHz PPDU. PPDUs exceeding an80 MHz bandwidth may include different U-SIGs.

The EHT-SIG of FIG. 18 may include control information for the receivingSTA. The EHT-SIG may be transmitted through at least one symbol, and onesymbol may have a length of 4 us. Information related to the number ofsymbols used for the EHT-SIG may be included in the U-SIG.

The EHT-SIG may include a technical feature of the HE-SIG-B describedwith reference to FIG. 8 and FIG. 9 . For example, the EHT-SIG mayinclude a common field and a user-specific field as in the example ofFIG. 8 . The common field of the EHT-SIG may be omitted, and the numberof user-specific fields may be determined based on the number of users.

As in the example of FIG. 8 , the common field of the EHT-SIG and theuser-specific field of the EHT-SIG may be individually coded. One userblock field included in the user-specific field may include informationfor two users, but a last user block field included in the user-specificfield may include information for one user. That is, one user blockfield of the EHT-SIG may include up to two user fields. As in theexample of FIG. 9 , each user field may be related to MU-MIMOallocation, or may be related to non-MU-MIMO allocation.

As in the example of FIG. 8 , the common field of the EHT-SIG mayinclude a CRC bit and a tail bit. A length of the CRC bit may bedetermined as 4 bits. A length of the tail bit may be determined as 6bits, and may be set to ‘000000’.

As in the example of FIG. 8 , the common field of the EHT-SIG mayinclude RU allocation information. The RU allocation information mayimply information related to a location of an RU to which a plurality ofusers (i.e., a plurality of receiving STAs) are allocated. The RUallocation information may be configured in unit of 8 bits (or N bits),as in Table 1.

The example of Table 5 to Table 7 is an example of 8-bit (or N-bit)information for various RU allocations. An index shown in each table maybe modified, and some entries in Table 5 to Table 7 may be omitted, andentries (not shown) may be added.

The example of Table 5 to Table 7 relates to information related to alocation of an RU allocated to a 20 MHz band. For example, ‘an index 0’of Table 5 may be used in a situation where nine 26-RUs are individuallyallocated (e.g., in a situation where nine 26-RUs shown in FIG. 5 areindividually allocated).

Meanwhile, a plurality or RUs may be allocated to one STA in the EHTsystem. For example, regarding ‘an index 60’ of Table 6, one 26-RU maybe allocated for one user (i.e., receiving STA) to the leftmost side ofthe 20 MHz band, one 26-RU and one 52-RU may be allocated to the rightside thereof, and five 26-RUs may be individually allocated to the rightside thereof.

TABLE 5 Number of Indices #1 #2 #3 #4 #5 #6 #7 #8 #9 entries 0 26 26 2626 26 26 26 26 26 1 1 26 26 26 26 26 26 26 52 1 2 26 26 26 26 26 52 2626 1 3 26 26 26 26 26 52 52 1 4 26 26 52 26 26 26 26 26 1 5 26 26 52 2626 26 52 1 6 26 26 52 26 52 26 26 1 7 26 26 52 26 52 52 1 8 52 26 26 2626 26 26 26 1 9 52 26 26 26 26 26 52 1 10 52 26 26 26 52 26 26 1 11 5226 26 26 52 52 1 12 52 52 26 26 26 26 26 1 13 52 52 26 26 26 52 1 14 5252 26 52 26 26 1 15 52 52 26 52 52 1 16 26 26 26 26 26 106 1 17 26 26 5226 106 1 18 52 26 26 26 106 1 19 52 52 26 106 1

TABLE 6 Number of Indices #1 #2 #3 #4 #5 #6 #7 #8 #9 entries 20 106 2626 26 26 26 1 21 106 26 26 26 52 1 22 106 26 52 26 26 1 23 106 26 52 521 24 52 52 — 52 52 1 25 242-tone RU empty (with zero users) 1 26 106 26106 1 27-34 242 8 35-42 484 8 43-50 996 8 51-58 2*996 8 59 26 26 26 2626 52 + 26 26 1 60 26 26 + 52 26 26 26 26 26 1 61 26 26 + 52 26 26 26 521 62 26 26 + 52 26 52 26 26 1 63 26 26 52 26 52 + 26 26 1 64 26 26 + 5226 52 + 26 26 1 65 26 26 + 52 26 52 52 1

TABLE 7 66 52 26 26 26 52 + 26 26 1 67 52 52 26 52 + 26 26 1 68 52 52 +26 52 52 1 69 26 26 26 26 26 + 106 1 70 26 26 + 52 26 106 1 71 26 26 5226 + 106 1 72 26 26 + 52 26 + 106 1 73 52 26 26 26 + 106 1 74 52 52 26 +106 1 75 106 + 26 26 26 26 26 1 76 106 + 26 26 26 52 1 77 106 + 26 52 2626 1 78 106 26 52 + 26 26 1 79 106 + 26 52 + 26 26 1 80 106 + 26 52 52 181 106 + 26 106 1 82 106 26 + 106 1

A mode in which the common field of the EHT-SIG is omitted may besupported. The mode in which the common field of the EHT-SIG is omittedmay be called a compressed mode. When the compressed mode is used, aplurality of users (i.e., a plurality of receiving STAs) may decode thePPDU (e.g., the data field of the PPDU), based on non-OFDMA. That is,the plurality of users of the EHT PPDU may decode the PPDU (e.g., thedata field of the PPDU) received through the same frequency band.Meanwhile, when a non-compressed mode is used, the plurality of users ofthe EHT PPDU may decode the PPDU (e.g., the data field of the PPDU),based on OFDMA. That is, the plurality of users of the EHT PPDU mayreceive the PPDU (e.g., the data field of the PPDU) through differentfrequency bands.

The EHT-SIG may be configured based on various MCS schemes. As describedabove, information related to an MCS scheme applied to the EHT-SIG maybe included in U-SIG. The EHT-SIG may be configured based on a DCMscheme. For example, among N data tones (e.g., 52 data tones) allocatedfor the EHT-SIG, a first modulation scheme may be applied to half ofcontiguous tones, and a second modulation scheme may be applied to theremaining half of the contiguous tones. That is, a transmitting STA mayuse the first modulation scheme to modulate specific control informationthrough a first symbol and allocate it to half of the contiguous tones,and may use the second modulation scheme to modulate the same controlinformation by using a second symbol and allocate it to the remaininghalf of the contiguous tones. As described above, information (e.g., a1-bit field) regarding whether the DCM scheme is applied to the EHT-SIGmay be included in the U-SIG.

An HE-STF of FIG. 18 may be used for improving automatic gain controlestimation in a multiple input multiple output (MIMO) environment or anOFDMA environment. An HE-LTF of FIG. 18 may be used for estimating achannel in the MIMO environment or the OFDMA environment.

The EHT-STF of FIG. 18 may be set in various types. For example, a firsttype of STF (e.g., 1×STF) may be generated based on a first type STFsequence in which a non-zero coefficient is arranged with an interval of16 subcarriers. An STF signal generated based on the first type STFsequence may have a period of 0.8p, and a periodicity signal of 0.8 μsmay be repeated 5 times to become a first type STF having a length of 4μs. For example, a second type of STF (e.g., 2×STF) may be generatedbased on a second type STF sequence in which a non-zero coefficient isarranged with an interval of 8 subcarriers. An STF signal generatedbased on the second type STF sequence may have a period of 1.6p, and aperiodicity signal of 1.6 μs may be repeated 5 times to become a secondtype STF having a length of 8 μs. Hereinafter, an example of a sequencefor configuring an EHT-STF (i.e., an EHT-STF sequence) is proposed. Thefollowing sequence may be modified in various ways.

The EHT-STF may be configured based on the following sequence M.

M={−1,−1,−1,1,1,1,−1,1,1,1,−1,1,1,−1,1}  <Equation 1>

The EHT-STF for the 20 MHz PPDU may be configured based on the followingequation. The following example may be a first type (i.e., 1×STF)sequence. For example, the first type sequence may be included in not atrigger-based (TB) PPDU but an EHT-PPDU. In the following equation,(a:b:c) may imply a duration defined as b tone intervals (i.e., asubcarrier interval) from a tone index (i.e., subcarrier index) ‘a’ to atone index ‘c’. For example, the equation 2 below may represent asequence defined as 16 tone intervals from a tone index −112 to a toneindex 112. Since a subcarrier spacing of 78.125 kHz is applied to theEHT-STR, the 16 tone intervals may imply that an EHT-STF coefficient (orelement) is arranged with an interval of 78.125*16=1250 kHz. Inaddition, * implies multiplication, and sqrt( ) implies a square root.In addition, j implies an imaginary number.

EHT-STF(−112:16:112)={M}*(1+j)/sqrt(2)  <Equation 2>

EHT-STF(0)=0

The EHT-STF for the 40 MHz PPDU may be configured based on the followingequation. The following example may be the first type (i.e., 1×STF)sequence.

EHT-STF(−240:16:240)={M,0,−M}*(1+j)/sqrt(2)  <Equation 3>

The EHT-STF for the 80 MHz PPDU may be configured based on the followingequation. The following example may be the first type (i.e., 1×STF)sequence.

EHT-STF(−496:16:496)={M,1,−M,0,−M,1,−M}*(1+j)/sqrt(2)  <Equation 4>

The EHT-STF for the 160 MHz PPDU may be configured based on thefollowing equation. The following example may be the first type (i.e.,1×STF) sequence.

EHT-STF(−1008:16:1008)={M,1,−M,0,−M,1,−M,0,−M,—1,M,0,−M,1,−M}*(1+j)/sqrt(2)  <Equation5>

In the EHT-STF for the 80+80 MHz PPDU, a sequence for lower 80 MHz maybe identical to Equation 4. In the EHT-STF for the 80+80 MHz PPDU, asequence for upper 80 MHz may be configured based on the followingequation.

EHT-STF(−496:16:496)={−M,−1,M,0,−M,1,−M}*(1+j)/sqrt(2)  <Equation 6>

Equation 7 to Equation 11 below relate to an example of a second type(i.e., 2×STF) sequence.

EHT-STF(−120:8:120)={M,0,−M}*(1+j)/sqrt(2)  <Equation 7>

The EHT-STF for the 40 MHz PPDU may be configured based on the followingequation.

EHT-STF(−248:8:248)={M,—1,−M,0,M,—1,M}*(1+j)/sqrt(2)  <Equation 8>

EHT-STF(−248)=0

EHT-STF(248)=0

The EHT-STF for the 80 MHz PPDU may be configured based on the followingequation.

EHT-STF(−504:8:504)={M,−1,M,−1,−M,−1,M,0,−M,1,M,1,−M,1,−M}*(1+j)/sqrt(2)  <Equation9>

The EHT-STF for the 160 MHz PPDU may be configured based on thefollowing equation.

EHT-STF(−1016:16:1016)={M,−1,M,−1,−M,−1,M,0,−M,1,M,1,−M,1,−M,0,−M,1,−M,1,M,1,−M,0,−M,1,M,1,−M,1,−M}*(1+j)/sqrt(2)  <Equation 10>

EHT-STF(−8)=0, EHT-STF(8)=0,

EHT-STF(−1016)=0, EHT-STF(1016)=0

In the EHT-STF for the 80+80 MHz PPDU, a sequence for lower 80 MHz maybe identical to Equation 9. In the EHT-STF for the 80+80 MHz PPDU, asequence for upper 80 MHz may be configured based on the followingequation.

EHT-STF(−504:8:504)={−M,1,−M,1,M,1,−M,0,−M,1,M,1,−M,1,−M}*(1+j)/sqrt(2)  <Equation11>

EHT-STF(−504)=0,

EHT-STF(504)=0

The EHT-LTF may have first, second, and third types (i.e., 1×, 2×,4×LTF). For example, the first/second/third type LTF may be generatedbased on an LTF sequence in which a non-zero coefficient is arrangedwith an interval of 4/2/1 subcarriers. The first/second/third type LTFmay have a time length of 3.2/6.4/12.8 μs. In addition, a GI (e.g.,0.8/1/6/3.2 μs) having various lengths may be applied to thefirst/second/third type LTF.

Information related to a type of STF and/or LTF (information related toa GI applied to LTF is also included) may be included in a SIG-A fieldand/or SIG-B field or the like of FIG. 18 .

A PPDU (e.g., EHT-PPDU) of FIG. 18 may be configured based on theexample of FIG. 5 and FIG. 6 .

For example, an EHT PPDU transmitted on a 20 MHz band, i.e., a 20 MHzEHT PPDU, may be configured based on the RU of FIG. 5 . That is, alocation of an RU of EHT-STF, EHT-LTF, and data fields included in theEHT PPDU may be determined as shown in FIG. 5 .

An EHT PPDU transmitted on a 40 MHz band, i.e., a 40 MHz EHT PPDU, maybe configured based on the RU of FIG. 6 . That is, a location of an RUof EHT-STF, EHT-LTF, and data fields included in the EHT PPDU may bedetermined as shown in FIG. 6 .

Since the RU location of FIG. 6 corresponds to 40 MHz, a tone-plan for80 MHz may be determined when the pattern of FIG. 6 is repeated twice.That is, an 80 MHz EHT PPDU may be transmitted based on a new tone-planin which not the RU of FIG. 7 but the RU of FIG. 6 is repeated twice.

When the pattern of FIG. 6 is repeated twice, 23 tones (i.e., 11 guardtones+12 guard tones) may be configured in a DC region. That is, atone-plan for an 80 MHz EHT PPDU allocated based on OFDMA may have 23 DCtones. Unlike this, an 80 MHz EHT PPDU allocated based on non-OFDMA(i.e., a non-OFDMA full bandwidth 80 MHz PPDU) may be configured basedon a 996-RU, and may include 5 DC tones, 12 left guard tones, and 11right guard tones.

A tone-plan for 160/240/320 MHz may be configured in such a manner thatthe pattern of FIG. 6 is repeated several times.

The PPDU of FIG. 18 may be determined (or identified) as an EHT PPDUbased on the following method.

A receiving STA may determine a type of an RX PPDU as the EHT PPDU,based on the following aspect. For example, the RX PPDU may bedetermined as the EHT PPDU: 1) when a first symbol after an L-LTF signalof the RX PPDU is a BPSK symbol; 2) when RL-SIG in which the L-SIG ofthe RX PPDU is repeated is detected; and 3) when a result of applying“modulo 3” to a value of a length field of the L-SIG of the RX PPDU isdetected as “0”. When the RX PPDU is determined as the EHT PPDU, thereceiving STA may detect a type of the EHT PPDU (e.g., anSU/MU/Trigger-based/Extended Range type), based on bit informationincluded in a symbol after the RL-SIG of FIG. 18 . In other words, thereceiving STA may determine the RX PPDU as the EHT PPDU, based on: 1) afirst symbol after an L-LTF signal, which is a BPSK symbol; 2) RL-SIGcontiguous to the L-SIG field and identical to L-SIG; 3) L-SIG includinga length field in which a result of applying “modulo 3” is set to “0”;and 4) a 3-bit PHY version identifier of the aforementioned U-SIG (e.g.,a PHY version identifier having a first value).

For example, the receiving STA may determine the type of the RX PPDU asthe EHT PPDU, based on the following aspect. For example, the RX PPDUmay be determined as the HE PPDU: 1) when a first symbol after an L-LTFsignal is a BPSK symbol; 2) when RL-SIG in which the L-SIG is repeatedis detected; and 3) when a result of applying “modulo 3” to a value of alength field of the L-SIG is detected as “1” or “2”.

For example, the receiving STA may determine the type of the RX PPDU asa non-HT, HT, and VHT PPDU, based on the following aspect. For example,the RX PPDU may be determined as the non-HT, HT, and VHT PPDU: 1) when afirst symbol after an L-LTF signal is a BPSK symbol; and 2) when RL-SIGin which L-SIG is repeated is not detected. In addition, even if thereceiving STA detects that the RL-SIG is repeated, when a result ofapplying “modulo 3” to the length value of the L-SIG is detected as “0”,the RX PPDU may be determined as the non-HT, HT, and VHT PPDU.

In the following example, a signal represented as a (TX/RX/UL/DL)signal, a (TX/RX/UL/DL) frame, a (TX/RX/UL/DL) packet, a (TX/RX/UL/DL)data unit, (TX/RX/UL/DL) data, or the like may be a signaltransmitted/received based on the PPDU of FIG. 18 . The PPDU of FIG. 18may be used to transmit/receive frames of various types. For example,the PPDU of FIG. 18 may be used for a control frame. An example of thecontrol frame may include a request to send (RTS), a clear to send(CTS), a power save-poll (PS-poll), BlockACKReq, BlockAck, a null datapacket (NDP) announcement, and a trigger frame. For example, the PPDU ofFIG. 18 may be used for a management frame. An example of the managementframe may include a beacon frame, a (re-)association request frame, a(re-)association response frame, a probe request frame, and a proberesponse frame. For example, the PPDU of FIG. 18 may be used for a dataframe. For example, the PPDU of FIG. 18 may be used to simultaneouslytransmit at least two or more of the control frame, the managementframe, and the data frame.

FIG. 19 illustrates an example of a modified transmission device and/orreceiving device of the present specification.

Each device/STA of the sub-figure (a)/(b) of FIG. 1 may be modified asshown in FIG. 19 . A transceiver 630 of FIG. 19 may be identical to thetransceivers 113 and 123 of FIG. 1 . The transceiver 630 of FIG. 19 mayinclude a receiver and a transmitter.

A processor 610 of FIG. 19 may be identical to the processors 111 and121 of FIG. 1 . Alternatively, the processor 610 of FIG. 19 may beidentical to the processing chips 114 and 124 of FIG. 1 .

A memory 620 of FIG. 19 may be identical to the memories 112 and 122 ofFIG. 1 . Alternatively, the memory 620 of FIG. 19 may be a separateexternal memory different from the memories 112 and 122 of FIG. 1 .

Referring to FIG. 19 , a power management module 611 manages power forthe processor 610 and/or the transceiver 630. A battery 612 suppliespower to the power management module 611. A display 613 outputs a resultprocessed by the processor 610. A keypad 614 receives inputs to be usedby the processor 610. The keypad 614 may be displayed on the display613. A SIM card 615 may be an integrated circuit which is used tosecurely store an international mobile subscriber identity (IMSI) andits related key, which are used to identify and authenticate subscriberson mobile telephony devices such as mobile phones and computers.

Referring to FIG. 19 , a speaker 640 may output a result related to asound processed by the processor 610. A microphone 641 may receive aninput related to a sound to be used by the processor 610.

Hereinafter, technical features of channel bonding supported by the STAof the present disclosure will be described.

For example, in an IEEE 802.11n system, 40 MHz channel bonding may beperformed by combining two 20 MHz channels. In addition, 40/80/160 MHzchannel bonding may be performed in the IEEE 802.11ac system.

For example, the STA may perform channel bonding for a primary 20 MHzchannel (P20 channel) and a secondary 20 MHz channel (S20 channel). Abackoff count/counter may be used in the channel bonding process. Thebackoff count value may be chosen as a random value and decrementedduring the backoff interval. In general, when the backoff count valuebecomes 0, the STA may attempt to access the channel.

During the backoff interval, when the P20 channel is determined to be inthe idle state and the backoff count value for the P20 channel becomes0, the STA, performing channel bonding, determines whether an S20channel has maintained an idle state for a certain period of time (forexample, point coordination function interframe space (PIFS)). If theS20 channel is in an idle state, the STA may perform bonding on the P20channel and the S20 channel. That is, the STA may transmit a signal(PPDU) through a 40 MHz channel (that is, a 40 MHz bonding channel)including a P20 channel and the S20 channel.

FIG. 20 shows an example of channel bonding. As shown in FIG. 20 , theprimary 20 MHz channel and the secondary 20 MHz channel may make up a 40MHz channel (primary 40 MHz channel) through channel bonding. That is,the bonded 40 MHz channel may include a primary 20 MHz channel and asecondary 20 MHz channel.

Channel bonding may be performed when a channel contiguous to theprimary channel is in an idle state. That is, the Primary 20 MHzchannel, the Secondary 20 MHz channel, the Secondary 40 MHz channel, andthe Secondary 80 MHz channel can be sequentially bonded. However, if thesecondary 20 MHz channel is determined to be in the busy state, channelbonding may not be performed even if all other secondary channels are inthe idle state. In addition, when it is determined that the secondary 20MHz channel is in the idle state and the secondary 40 MHz channel is inthe busy state, channel bonding may be performed only on the primary 20MHz channel and the secondary 20 MHz channel.

Hereinafter, preamble puncturing supported by a STA in the presentdisclosure will be described.

For example, in the example of FIG. 20 , if the Primary 20 MHz channel,the Secondary 40 MHz channel, and the Secondary 80 MHz channel are allin the idle state, but the Secondary 20 MHz channel is in the busystate, bonding to the secondary 40 MHz channel and the secondary 80 MHzchannel may not be possible. In this case, the STA may configure a 160MHz PPDU and may perform a preamble puncturing on the preambletransmitted through the secondary 20 MHz channel (for example, L-STF,L-LTF, L-SIG, RL-SIG, U-SIG, HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF,EHT-SIG, EHT-STF, EHT-LTF, etc.), so that the STA may transmit a signalthrough a channel in the idle state. In other words, the STA may performpreamble puncturing for some bands of the PPDU. Information on preamblepuncturing (for example, information about 20/40/80 MHz channels/bandsto which puncturing is applied) may be included in a signal field (forexample, HE-SIG-A, U-SIG, EHT-SIG) of the PPDU.

Hereinafter, technical features of a multi-link (ML) supported by a STAof the present disclosure will be described.

The STA (AP and/or non-AP STA) of the present disclosure may supportmulti-link (ML) communication. ML communication may refer tocommunication supporting a plurality of links. The link related to MLcommunication may include channels of the 2.4 GHz band shown in FIG. 15, the 5 GHz band shown in FIG. 16 , and the 6 GHz band shown in FIG. 17(for example, 20/40/80/160/240/320 MHz channels).

A plurality of links used for ML communication may be set in variousways. For example, a plurality of links supported by one STA for MLcommunication may be a plurality of channels in a 2.4 GHz band, aplurality of channels in a 5 GHz band, and a plurality of channels in a6 GHz band. Alternatively, a plurality of links supported by one STA forML communication may be a combination of at least one channel in the 2.4GHz band (or 5 GHz/6 GHz band) and at least one channel in the 5 GHzband (or 2.4 GHz/6 GHz band). Meanwhile, at least one of the pluralityof links supported by one STA for ML communication may be a channel towhich preamble puncturing is applied.

The STA may perform an ML setup to perform ML communication. The MLsetup may be performed based on a management frame or control frame suchas a Beacon, a Probe Request/Response, an Association Request/Response,and the like. For example, information about ML setup may be included inan element field included in a Beacon, a Probe Request/Response, anAssociation Request/Response, and the like.

When ML setup is completed, an enabled link for ML communication may bedetermined. The STA may perform frame exchange through at least one of aplurality of links determined as an enabled link. For example, theenabled link may be used for at least one of a management frame, acontrol frame, and a data frame.

When one STA supports multiple links, a transceiver supporting each linkmay operate as one logical STA. For example, one STA supporting twolinks may be expressed as one Multi Link Device (MLD) including a firstSTA for the first link and a second STA for the second link. Forexample, one AP supporting two links may be expressed as one AP MLDincluding a first AP for a first link and a second AP for a second link.In addition, one non-AP supporting two links may be expressed as onenon-AP MLD including a first STA for the first link and a second STA forthe second link.

Hereinafter, more specific features related to the ML setup aredescribed.

The MLD (AP MLD and/or non-AP MLD) may transmit, through ML setup,information on a link that the corresponding MLD can support. Linkinformation may be configured in various ways. For example, informationon the link may include at least one of 1) information on whether theMLD (or STA) supports simultaneous RX/TX operation, 2) information onthe number/upper limit of uplink/downlink links supported by the MLD (orSTA), 3) information on the location/band/resource of theuplink/downlink Link supported by the MLD (or STA), 4) information onthe frame type (management, control, data, etc.) available or preferredin at least one uplink/downlink link, 5) information on ACK policyavailable or preferred in at least one uplink/downlink link, and 6)information on an available or preferred traffic identifier (TID) in atleast one uplink/downlink Link. The TID is related to the priority oftraffic data and is expressed as eight types of values according to theconventional wireless LAN standard. That is, eight TID valuescorresponding to four access categories (ACs) (AC_Background (AC_BK),AC_Best Effort (AC_BE), AC_Video (AC_VI), AC_Voice (AC_VO)) according tothe conventional WLAN standard may be defined.

For example, it may be preset that all TIDs are mapped foruplink/downlink link. Specifically, if negotiation is not made throughML setup, if all TIDs are used for ML communication, and if the mappingbetween uplink/downlink link and TID is negotiated through additional MLsettings, the negotiated TID may be used for ML communication.

Through ML setup, a plurality of links usable by the transmitting MLDand the receiving MLD related to ML communication may be set, and thismay be referred to as an “enabled link”. The “enabled link” may becalled differently in various expressions. For example, it may bereferred to as various expressions such as a first link, a second link,a transmission link, and a reception link.

After the ML setup is completed, the MLD could update the ML setup. Forexample, the MLD may transmit information on a new link when it isnecessary to update information on the link. Information on the new linkmay be transmitted based on at least one of a management frame, acontrol frame, and a data frame.

In extreme high throughput (EHT), a standard being discussed afterIEEE802.11ax, the introduction of HARQ is being considered. When HARQ isintroduced, coverage can be expanded in a low signal to noise ratio(SNR) environment, that is, in an environment where the distance betweenthe transmitting terminal and the receiving terminal is long, and higherthroughput may be obtained in a high SNR environment.

The device described below may be the apparatus of FIGS. 1 and/or 19 ,and the PPDU may be the PPDU of FIG. 18 . A device may be an AP or anon-AP STA. The device described below may be an AP multi-link device(MLD) supporting multi-link or a non-AP STA MLD.

In extremely high throughput (EHT), a standard being discussed after802.11ax, a multi-link environment using one or more bands at the sametime is being considered. When the device supports multi-link ormulti-link, the device may use one or more bands (for example, 2.4 GHz,5 GHz, 6 GHz, 60 GHz, etc.) simultaneously or alternately. Multi-linktransmission can be classified into two types as shown in FIG. 21 .

Referring to FIG. 21 , there may be two methods of multi-linktransmission, synchronous transmission and asynchronous transmission.

In the existing single band/single link situation, the ACK frame may betransmitted through the band/link through which data is transmitted.Therefore, when the transmission is performed in two or morebands/links, the ACK frame for data transmitted in each link may operatein a link-specific manner. The ACK frame could be lost due to a powerimbalance problem or a collision problem between devices. The linkquality of a specific link could be lower than that of another link dueto a frequency characteristic or a difference in OBSS density. That is,a reliability difference between links may occur. In the multi-linkenvironment described below, time resources can be more efficiently usedby designing a reliable ACK transmission procedure using multi-links.

Hereinafter, a BA frame transmission method using a multi-linkenvironment will be described. Hereinafter, in order to transmit areliable BA frame, a BA frame including a transmission result of anotherband/link may be duplicated and transmitted in each band/link.Hereinafter, an ACK frame configuration and transmission method will bedescribed for a case in which multi-link transmission is synchronous,that is, the transmission of each band is aligned, and asynchronous,that is, a case where transmission is performed independently. Forexample, a synchronous transmission method with the same transmissiontime point and end point in different bands/links, and an asynchronoustransmission method with different transmission time points anddifferent end points on different bands/links may be described. Thereceiving terminal can obtain the effect of efficiently using radioresources by notifying the transmitting terminal of a problem occurringin frame transmission and reception of a specific band or a specificlink through another band or another link.

Hereinafter, a block ACK (BA) frame may be proposed as an example of aresponse to a data frame, but a response to the data frame may beconfigured in various other forms. Hereinafter, an ACK frame, a BAframe, a compressed BA frame, or the like may be used, but for theconvenience of the description, some embodiments may be described basedon the BA frame.

Hereinafter, although described in the form of a multi-link, thefrequency band may be configured in various other forms. Although termssuch as multi-link and multi-link may be used in this specification,some embodiments may be described based on multi-link for theconvenience of the description below.

In the following specification, an acknowledgement (ACK) transmissionmethod in synchronous transmission and asynchronous transmission will bedescribed. Synchronous transmission refers to a method in which thetransmission end time of two specific PPDUs transmitted by a device ismatched through negotiation or an indication or arranged process betweenlinks within the device. Asynchronous transmission refers to a method oftransmission without additional means to match the end time of the PPDUfor transmission in any two or more links.

In the following specification, the Ack frame may be expressed through abitmap extension of the previously used Block Ack frame, or a new Ackframe format may be created and used, but the method is not limitedthereto.

In the following specification, an MLD refers to a multi-link device.The MLD has one or more connected STAs and one MAC service access point(SAP) that connects to an upper link layer (Logical Link Control, LLC).MLD may mean a physical device or a logical device. Hereinafter, adevice may mean an MLD.

In the following specification, a transmitting device and a receivingdevice may refer to an MLD. The first link of the receiving/transmittingdevice may be a terminal (for example, STA or AP) that performs signaltransmission/reception through the first link included in thereceiving/transmitting device. The second link of thereceiving/transmitting device may be a terminal (for example, STA or AP)that performs signal transmission/reception through the second linkincluded in the receiving/transmitting device. That is, thereceiving/transmitting device is

1. Synchronous Multi-Link Transmission

FIG. 22 is a diagram showing an example of synchronous multi-linktransmission. In the case of a synchronous multi-link environment, a BAframe may be transmitted as shown in FIG. 22 .

Referring to FIG. 22 , a BA frame including two BAs (for example, ACK1and ACK2) may be transmitted at the same time. For example, ACK1 may bea BA for DATA1, and ACK2 may be a BA for DATA2. The number of links onwhich signals are transmitted at the same time may be two or more, or inorder to increase robustness and reliability of transmission, a responsesignal (that is, BA frame) including two or more BAs may be transmitted.If two or more BAs are included in the BA frame, even if thetransmitting STA receives a response signal from another link, if thetransmitting STA receives a response signal from another link, it canobtain the effect of successfully acquiring ACK/NACK information of thepreviously transmitted data frame.

DATA1 and/or DATA2 may be one PPDU. Multiple MPDUs may exist in the dataframe of the PPDU. ACK1 or ACK2 may also be one PPDU. The Ack frame maybe a BlockAck frame, and the ACK frame may include Ack information for aplurality of MPDUs.

After receiving the data frame, and after completing the scoreboardingprocess for DATA1 and DATA2 received from Link A/B (or Band A/B), thereceiving device should deliver acknowledgement (ACK) information forDATA1 or DATA2 to another link within a short inter frame space (SIFS)interval. For example, the receiving device should deliver the ACKinformation of DATA1 received through Link A to Link B of the receivingdevice in SIFS, the receiving device should deliver the ACK informationof DATA2 received through Link B to Link A of the receiving device inSIFS. Ack policy related to the data frame may be Ack PolicyIndicator=‘00’, which means Normal Ack or implicit BAR.

The link of the receiving device (for example, link A of the receivingdevice) may receive scoreboard information of another link (for example,link B of the receiving device). Link A of the receiving device may beused for transmitting an ACK frame (for example, ACK1+ACK2) in which ACKinformation for DATA (for example, DATA1) received by its link (e.g.link A) and ACK information for DATA (for example, DATA2) received fromanother link (e.g. link B) are collected, after SIFS. Aggregated ACK maybe transmitted only on a specific link. For example, it is also possibleto transmit only ACK1+ACK2 in link A and ACK2 in link B as shown in FIG.24 . The above-mentioned transmission method can be equally applied tothe transmission type using the BlockAck request.

FIG. 23 is a diagram showing an example of synchronous multi-linktransmission.

Referring to FIG. 23 , a device receiving a data frame from link A andlink B may configure BlockACK information based on a result of decodingand CRC check of the received data. The BA frame may be configured bymerging the BlockACK information of the link A and the link B. Themerged BA frame may be duplicated in link A and link B and transmittedto the AP. For example, the BA frame may include both a BA for data 1transmitted from link A (that is, ACK1) and a BA for data 2 transmittedfrom link B (that is, ACK2). Although in this embodiment, downlink (DL)transmission is assumed, but the same method may be used for uplink (UL)transmission.

Even when the BA frame is lost due to power imbalance or collision,since transmission information of all links is included in the BA frame,the transmitting device may know that the reception has been successful.For example, when the receiving device successfully receives data1 onlink A and data2 on link B, when the BA frames (that is, ACK1, ACK2) fordata 1 and data 2 transmitted by the receiving device through link B arelost, since the transmitting device can receive BA frames for data1 anddata2 through link A, the transmitting device may acquire informationthat data1 and data2 have been successfully received.

FIGS. 24 and 25 are diagrams illustrating an embodiment of a synchronousmulti-link ACK transmission method.

FIG. 24 shows an embodiment of an acknowledgment aggregated only in aspecific link. Referring to FIG. 24 , a receiving device may receive adata frame. Link B of the receiving device should deliver the ACKinformation for DATA2 to Link A of the receiving device within the SIFSinterval, after completing the scoreboarding process for the receivedDATA2. Ack policy indicated in the data frame may be Ack PolicyIndicator=“00”, which means Normal Ack or implicit BAR. After receivingscoreboard information of Link B (that is, ACK information for DATA2),after SIFS, Link A collects it with ACK information for DATA1 receivedby link A, and responds it in the form of ACK 1+ACK 2. That is, link Aof the receiving device may be used for transmitting an ACK frame (forexample, ACK1+ACK2) in which ACK information for DATA (for example,DATA1) received by its link (e.g. link A) and ACK information for DATA(for example, DATA2) received from another link (e.g. link B) arecollected, after SIFS.

Link B may transmit an ACK frame (for example, ACK 2) including only ACKinformation for the received DATA 2. The embodiment of FIG. 24 can beequally applied to a transmission form using a BlockAck request. FIG. 25shows an embodiment when a BAR frame is used.

FIGS. 26 to 33 show embodiments of a method for transmitting asynchronous multi-link ACK.

FIGS. 26, 28, 30, and 32 are embodiments of a method for includinginformation on which data a transmitting STA requests ACK for in a dataframe, and FIGS. 27, 29, 31, and 33 are embodiments of a method forincluding information on which data a transmitting STA requests for ACKin a block ACK request (BAR) frame. For example, the data may includeinformation related to an ACK policy.

FIGS. 26 and 27 are embodiments of a method for configuring a BA frameby merging BA information (that is, information related to whether ornot data has been received) for data transmitted from different links bya receiving STA, and then duplicating and transmitting the same BA framein each link.

FIGS. 28 and 29 are embodiments of a method for merging and transmittingonly BAs for data received in each link by a receiving STA (that is,information related to whether data is received).

FIGS. 30 and 31 are embodiments of a method for transmitting only onelink, after constructing a BA frame including BAs for all data receivedby a receiving STA (that is, information related to whether or not alldata has been received).

FIGS. 32 and 33 are embodiments of a method for transmitting a BA framein which BA information for data transmitted from another link is merged(that is, information related to whether or not data has been received)through a specific link, and transmitting a BA frame including only ACKinformation of the corresponding link through the other link.

In the embodiments of FIGS. 26 to 33 , DL transmission is assumed, butthe same method may be used for UL transmission.

The receiving device receiving the data frame from the link A and thelink B may configure BA information based on the decoding and CRC checkresults of the received data, and may configure the BA frame by mergingthe BA information.

2. Asynchronous Multi-Band Transmission

FIG. 34 is a diagram showing an example of asynchronous multi-linktransmission. In the case of an asynchronous multi-link environment, aBA frame may be transmitted as shown in FIG. 34 .

Referring to FIG. 34 , a BA frame including two recent BAs (for example,ACK1 and ACK2) may be transmitted. For example, ACK1 may be a BA forDATA1, and ACK2 may be a BA for DATA2. The number of links on whichsignals are transmitted may be two or more, or in order to increaserobustness and reliability of transmission, a response signal (that is,BA frame) including two or more BAs may be transmitted. If two or moreBAs are included in the BA frame, even if the transmitting devicereceives a response signal from another link, if the transmitting devicereceives a response signal from another link, it can obtain the effectof successfully acquiring ACK/NACK information of the previouslytransmitted data frame.

The receiving device, receiving the data frame in an arbitrary band, mayconfigure the BA frame by merging BA information on data previouslyreceived in another link. For example, the receiving device mayconfigure a BA frame by merging BA information on data 2 received inband B and BA information on data 1 previously received in band A. Themerged BA frame may be transmitted to the transmitting device in thecorresponding band. For example, the merged BA frame may be transmittedthrough band B in which data 2 is received. In this embodiment, downlink(DL) transmission is assumed, but the same method may be used for uplink(UL) transmission.

FIG. 35 is a diagram showing an example of asynchronous multi-linktransmission.

Referring to FIG. 35 , even when a BA frame is lost due to powerimbalance or collision, since transmission information of a lost link isincluded in a BA frame transmitted through another link, thetransmitting device can know that the reception was successful. Forexample, if the receiving device successfully receives data 2 in band B,when the BA frames (that is, ACK1, ACK2) for data 1 and data 2transmitted by the receiving device through band B are lost, since thetransmitting device can receive BA frames for data2 and data3 throughband A, the transmitting device may obtain information that data2 hasbeen successfully received.

FIGS. 36 and 37 are diagrams illustrating an example of an asynchronousmulti-link transmission method.

FIG. 36 shows an embodiment of an acknowledgment aggregated only in aspecific link. Referring to FIG. 36 , a receiving device may receive adata frame. Link A of the receiving device should deliver the ACKinformation for DATA1 to Link B of the receiving device within the SIFSinterval after completing the scoreboarding process for the receivedDATA1. In the case of asynchronous multi-link transmission, since datatransmission is transmitted asynchronously, ACK information of anotherlink may not be strictly transmitted within the SIFS interval as in thecase of synchronous transmission. Ack policy indicated in the data framemay be Ack Policy Indicator=“00”, which means Normal Ack or implicitBAR. Link B, which has received the scoreboard information of Link A(that is, ACK information for DATA1), combines it with the ACKinformation for DATA2 received by link B, and responds it in the form ofACK1+ACK2. That is, link A of the receiving device may be used fortransmitting an ACK frame (for example, ACK1+ACK2) in which ACKinformation for DATA (for example, DATA1) received by its link (e.g.link A) and ACK information for DATA (for example, DATA2) received fromanother link (e.g. link B) are collected, after SIFS.

Link B may transmit an ACK frame (for example, ACK 1) including only ACKinformation for the received DATA 2. The embodiment of FIG. 36 can beequally applied to a transmission form using a BlockAck request. FIG. 37shows an embodiment when a BAR frame is used.

FIGS. 38 to 41 show embodiments of an asynchronous multi-link ACKtransmission method.

For example, FIGS. 38 to 41 show a method of omitting transmission of aBA frame in a specific link and requesting an ACK for an earliertransmission in another link thereafter. For example, the data frame mayinclude information related to the ACK policy.

FIGS. 38 and 40 are an embodiment of a method in which a data frame (forexample, data 3) includes information related to which data an ACK isrequested. For example, data 3 of FIG. 38 may include informationrelated to ACK requests for data 1, data 2, and data 3. For example,data 3 of FIG. 40 may include information related to ACK requests fordata 1 and data 3.

FIGS. 39 and 41 are an embodiment of a method for including informationrelated to which data an ACK is requested in a BAR frame. For example,the BAR frame of FIG. 39 may include information related to an ACKrequest for data 1, data 2, and data 3. For example, the BAR frame ofFIG. 41 may include information related to ACK requests for data 1 anddata 3.

The receiving device may configure the BA frame by merging BAinformation on data in a link from which data has been recently receivedand BA information on data previously transmitted in another link. Thedata for which the transmitting device requests an ACK may include datathat was previously transmitted on the same link. For example, data 3transmitted on link A may include information related to an ACK requestfor data 1 previously transmitted on link A. The BA frame may betransmitted on a link that has recently received data. Although thisembodiment assumes downlink (DL) transmission, the same method may beused for uplink (UL) transmission.

For example, the receiving device may configure a BA frame by merging BAinformation for data received from different links, and transmit the BAframe on one link (for example, FIG. 38 and FIG. 39 ). For example, thereceiving device may configure a BA frame by merging only BA informationfor data received from each link, and transmit a BA frame for datareceived from each link through each link (for example, FIG. 40 , FIG.41 ). Although this embodiment assumes downlink (DL) transmission, thesame method may be used for uplink (UL) transmission.

3. Frame Format

For multi-link ACK, a field that can inform the receiving device aboutwhich data frame the transmitting device will request BA for (i.e.information related to receipt or not) may be required.

FIG. 42 is a diagram illustrating an embodiment of a PPDU used for datatransmission.

Referring to FIG. 42 , the PPDU may include a PHY header (PHYHDR) and aphysical service data unit (PSDU). PSDU may include MPDU delimiter,MPDU, and Padding fields. The MPDU (or data frame) may include a MACheader, a frame body, and an FCS field. The MAC header may include anEHT ACK control field. The EHT ACK control field may include a FragmentNumber (Frag. Number) field and a Sequence Number (Seq. Number) field.

The MAC header in the data frame of the PPDU used for data transmissionmay include a fragment number and a sequence number of a frame for whichACK is requested. The receiving device receiving the data frame mayobtain information on the frame for which the ACK is requested includedin the MAC header, and may transmit a BA frame including an ACK (thatis, information related to whether or not the ACK is received) for theframe for which ACK is requested. For example, a field capable ofinforming the receiving device about which data frame the transmittingdevice will request BA (that is, information related to whether or notit is received) may be defined for multi-link ACK. As a field capable ofinforming the receiving device about which data frame the transmittingdevice will request BA (i.e. information related to receipt or not), forexample, the EHT ACK control field may be defined, alternatively, otherreserved fields may be used. The position of the field that can informthe receiving device about which data frame the transmitting device willrequest a BA (that is, information related to whether or not it isreceived) is not limited thereto.

By including the ACK for the frame for which the ACK is requested (i.e.information related to receipt or not) in the data frame, there is aneffect that the transmitting device can specify the data frame fromwhich the response information is to be obtained. Accordingly, there isan effect that the transmitting device can efficiently determine whetherto retransmit.

FIG. 43 is a diagram illustrating an embodiment of a PPDU used for datatransmission.

Referring to FIG. 43 , a PPDU including an A-MPDU may include aplurality of A-MPDU subframes. In the MAC header of the A-MPDU subframe,a field (for example, EHT ACK control field) that can inform thereceiving device about which data frame the transmitting device willrequest BA (that is, information related to whether or not it isreceived) may be included. The EHT ACK control field may be included inat least one A-MPDU subframe. For example, the EHT ACK control field maybe included in only one A-MPDU subframe, in all A-MPDU subframes, or insome A-MPDU subframes.

Since the data frame includes an ACK for the frame for which the ACK isrequested (that is, information related to whether or not the ACK isreceived), there is the effect that the transmitting device can specifythe data frame from which the response information is to be obtained.Accordingly, there is the effect that the transmitting device canefficiently determine whether to retransmit.

FIG. 44 is a diagram illustrating an embodiment of a PPDU used for datatransmission.

Referring to FIG. 44 , the PSDU may include a field related to controlinformation for the entire A-MPDU (for example, an EHT ACK controlheader). The EHT ACK control header may be included in the PSDU, and theEHT ACK control header may include information related to which dataframe the transmitting device will request a BA (that is, informationrelated to whether it is received or not).

Since the data frame includes an ACK for the frame for which the ACK isrequested (that is, information related to whether or not the ACK isreceived), there is the effect that the transmitting device can specifythe data frame from which the response information is to be obtained.Accordingly, there is the effect that the transmitting device canefficiently determine whether to retransmit.

FIG. 45 is a diagram illustrating an embodiment of a PPDU used as a BAframe.

Referring to FIG. 45 , a PPDU used as a BA frame may include a PHYheader (PHYHDR) and a physical service data unit (PSDU). PSDU mayinclude MPDU delimiter, MPDU, and Padding fields. The MPDU may include aMAC header, a frame body, and an FCS field. The MAC header may includeFrame Control, Duration, RA, TA, BA Control, and BA Information fields.The BA Control field may include BA ACK policy, BA Type, Reserved, andTID information (INFO) fields. The BA Information field may include PerTID info, BlockAck Number, Block Ack Starting Sequence Control, andBlockAck Bitmap fields. The Block Ack Starting Sequence Control fieldmay include a Fragment Number and a Sequence Number field.

When the receiving device receives the data frame, it should transmitthe BlockAck frame including the ACK information of the solicited dataframe. For example, when the receiving device receives a PPDU includingdata, the receiving device may transmit a BA frame including ACKinformation for data frames for which a response related to whether toreceive is requested. The receiving device may obtain information ondata frames, for which a response related to whether to receive isrequested, through a data frame or a BAR frame.

The BA frame may include information indicating that the BA frameincludes BA information for multi-link. For example, it is possible toindicate that the BA frame is an EHT multi-link BA frame by using the BAtype spare field included in the BA frame. For example, if the BA typespare field included in the BA frame has a specific value, the BA framemay include information that the BA frame is an EHT multi-link BA frame.For example, if the BA type included in the BA frame has a value of 15,it may mean that the BA frame is a BA frame including ACK informationfor multi-link.

The BA Information field may include information on a fragment numberand a sequence number of data for which a response related to whethereach traffic identifier (TID) is received or not. For example, thefragment number and the sequence number may be included in the Block AckStarting Sequence Control field. ACK information of data for which aresponse related to reception is requested (that is, reception status)may be included in the BlockAck Bitmap field. When it is necessary totransmit ACK information for one or more TIDs, the Per TID info fieldmay include information on TIDs of data. The BlockAck number field mayinclude information on which fragment and/or sequence the ACK is for.

By including information that the BA frame contains responses to aplurality of links, there may be the effect that the transmitting devicecan obtain response information for data received in the current linkfrom a response signal received in another link based on the informationincluded in the response signal, or can deliver response information ofother links.

FIG. 46 is a diagram illustrating an embodiment of a PPDU used as a BAframe.

FIG. 46 may be a BA frame format transmitted when a receiving devicereceives a request for ACKs for all fragments of the same sequence. TheBA Information field may include information about a sequence number andmay include a Concatenated BlockAck Bitmap field. For example, theConcatenated BlockAck Bitmap field may include a BlockAck Bitmap fieldfor a plurality of fragments.

Information that the BA frame includes ACK information for a pluralityof links may be transmitted based on a new field or a new value, or itmay be included in other unused fields (for example, reserved fields,etc.). That is, the position of the field including informationindicating that the BA frame includes ACK information for a plurality oflinks is not limited.

The transmitting device and the receiving device may negotiate on an ACKresponse method. Negotiation may be performed through an action frame,or may be performed through an arbitrary field included in each dataframe. Alternatively, the negotiation on the ACK response method may beperformed using an existing field included in the data frame.

By including information that the BA frame contains responses to aplurality of links, there may be the effect that the transmitting devicecan obtain response information for data received in the current linkfrom a response signal received in another link based on the informationincluded in the response signal, or can deliver response information ofother links.

FIG. 47 is a diagram illustrating an embodiment of a PPDU used as a BARframe.

FIG. 47 may be a format of a BA request (BAR) frame transmitted by atransmitting device. The BAR frame (that is, PPDU) may include a PHYheader (PHYHDR) and a physical service data unit (PSDU). PSDU mayinclude MPDU delimiter, MPDU, and Padding fields. The MPDU may include aMAC header, a frame body, and an FCS field. The MAC header may includeFrame Control, Duration, RA, TA, BA Control, and BA Information fields.The BA Control field may include BA ACK policy, BA Type, Soliciting LinkID bitmap, and TID information (INFO) fields. The request link bitmapfield may include information on a link for which ACK is requested. Forexample, the request link bitmap field may include link indicatorinformation for which ACK is requested.

For example, when configuring the merged ACK frame or selectivelyconfiguring the merged ACK frame in a specific link, the transmittingdevice may transmit information on which links ACK information should bemerged to configure the Block Ack frame to the receiving link (that is,the link on which the BAR frame is received) of the receiving devicethrough the BAR frame.

For example, the transmitting device may indicate the link ID definedthrough the reserved field of the BA Control field included in the BARframe in a bitmap format. That is, the BA Control field may include aLink ID of a link for which ACK information is requested.

For example, a soliciting ID bitmap field may be sorted based on thedefined link order, descending order or ascending order of ID, andwhether to request ACK information may be binary indicating. Forexample, the first bit may be related to whether to request ACKinformation for data transmitted from Link A, the second bit may berelated to whether to request ACK information for data transmitted fromLink B, and the x-th bit may be related to whether to request ACKinformation for data transmitted from Link X. For example, it maycorrespond to each bit of the request link bitmap in the order in whichthe Link ID is sorted in descending order, and a bit corresponding toeach link may include information related to whether ACK information isrequested for data transmitted in each link (1-bit informationindicating whether ACK is requested or not). For example, it maycorrespond to each bit of the request link bitmap in the order in whichthe Link ID is sorted in ascending order, and a bit corresponding toeach link may include information related to whether ACK information isrequested for data transmitted in each link (1-bit informationindicating whether ACK is requested or not).

The receiving device receiving the BAR frame may transmit the mergedmulti-link block ack frame based on the scoreboard of the specifiedlink. That is, the receiving device may transmit the BA frame based onwhether or not decoding of data received in the designated link issuccessful.

FIG. 48 is a diagram illustrating an embodiment of an operation of areceiving device.

Referring to FIG. 48 , the receiving device may receive first data andsecond data from the transmitting device (S4810). For example, thereceiving device may receive first data over a first link and receivesecond data over a second link.

The receiving device may receive a first block acknowledgment request(BAR) frame through the first link and may receive a second BAR framethrough the second link from the transmitting device (S4820). The firstand second BAR frames may include information related to a link forwhich acknowledgment (ACK) is requested.

For example, the first BAR frame may include information related to thefirst and second links, and the first BA frame may include informationrelated to acknowledgment (ACK) of the first data and the second data.

For example, the second BAR frame may include information related to thesecond link, and the second BA frame may include information related tothe ACK of the second data.

For example, the receiving device may receive third data from thetransmitting device through a second link. The first BAR frame mayinclude information related to the first and second links. The first BAframe may include information related to acknowledgment (ACK) of thefirst data, the second data, and the third data.

For example, the information related to the link for which ACK isrequested may include a first bit and a second bit, the first bit mayinclude information related to whether to request an ACK of the firstdata received through the first link, and the second bit may includeinformation related to whether to request an ACK of the second datareceived through the second link.

For example, the order of the first bit and the second bit may bedetermined according to a predefined link order.

For example, the second link of the receiving device may transmit ACKinformation for DATA2 to the first link of the receiving device withinthe SIFS interval after completing the scoreboarding process for thereceived DATA2. The Ack policy included in the first data and/or thesecond data may be Ack Policy Indicator=“00”, which means Normal Ack orimplicit BAR.

For example, after SIFS, the first link of the receiving device, thathas received the scoreboard information (that is, ACK information forDATA2) of the second link of the receiving device, may respond in theform of ACK 1+ACK 2 by combining it with ACK information for DATA1received by the first link. That is, after SIFS, the first link of thereceiving device may transmit an ACK frame (for example, ACK1+ACK2) inwhich ACK information for DATA (for example, DATA1) received by its ownlink (that is, the first link) and ACK information for DATA (forexample, DATA2) received from another link (for example, second link)are aggregated. For example, the second link may transmit an ACK frame(for example, ACK 2) including only ACK information for the receivedDATA 2.

The BAR frame (that is, PPDU) may include a PHY header (PHYHDR) and aphysical service data unit (PSDU). PSDU may include MPDU delimiter,MPDU, and Padding fields. The MPDU may include a MAC header, a framebody, and an FCS field. The MAC header may include Frame Control,Duration, RA, TA, BA Control, and BA Information fields. The BA Controlfield may include BA ACK policy, BA Type, Soliciting Link ID bitmap, andTID information (INFO) fields. The request link bitmap field may includeinformation on a link for which ACK is requested. For example, therequest link bitmap field may include link indicator information forwhich ACK is requested.

For example, when configuring the merged ACK frame or selectivelyconfiguring the merged ACK frame in a specific link, the transmittingdevice may transmit information on which links ACK information should bemerged to configure the Block Ack frame to the receiving link of thereceiving device (that is, the link on which the BAR frame is received)through the BAR frame.

For example, the transmitting device may indicate the link ID definedthrough the reserved field of the BA Control field included in the BARframe in a bitmap format. That is, the BA Control field may include aLink ID of a link for which ACK information is requested.

For example, a soliciting ID bitmap field may be sorted based on thedefined link order, descending order or ascending order of ID, and itmay binary indicate whether to request ACK information. For example, thefirst bit may be related to whether to request ACK information for datatransmitted in the first link, the second bit may be related to whetherto request ACK information for data transmitted on the second link, andthe x-th bit may be related to whether to request ACK information fordata transmitted from Link X. For example, it may correspond to each bitof the request link bitmap in the order in which the Link ID is sortedin descending order, and a bit corresponding to each link may includeinformation related to whether to request ACK information for datatransmitted in each link (1-bit information indicating whether ACK isrequested or not). For example, it may correspond to each bit of therequest link bitmap in the order in which the Link ID is sorted inascending order and a bit corresponding to each link may includeinformation related to whether to request ACK information for datatransmitted in each link (1-bit information indicating whether ACK isrequested or not).

The receiving device may transmit the BA frame to the transmittingdevice (S4830). For example, the receiving device receiving the BARframe may transmit the merged multi-link block ack frame based on thescoreboard of the specified link. That is, the receiving device maytransmit the BA frame based on whether decoding of data received in thedesignated link is successful or not.

FIG. 49 is a diagram illustrating an embodiment of an operation of atransmitting device.

Referring to FIG. 49 , the transmitting device may transmit first dataand second data to the receiving device (S4910). For example, thetransmitting device may transmit first data over the first link andtransmit second data over the second link.

The transmitting device may transmit a first block acknowledgmentrequest (BAR) frame through the first link and transmit a second BARframe through the second link to the receiving device (S4920). The firstand second BAR frames may include information related to a link forwhich acknowledgment (ACK) is requested.

For example, the first BAR frame may include information related to thefirst and second links, and the first BA frame may include informationrelated to acknowledgment (ACK) of the first data and the second data.

For example, the second BAR frame may include information related to thesecond link, and the second BA frame may include information related tothe ACK of the second data.

For example, the receiving device may receive third data from thetransmitting device through a second link. The first BAR frame mayinclude information related to the first and second links. The first BAframe may include information related to acknowledgment (ACK) of thefirst data, the second data, and the third data.

For example, the information related to the link for which ACK isrequested may include a first bit and a second bit, the first bit mayinclude information related to whether to request an ACK of the firstdata received through the first link, and the second bit may includeinformation related to whether to request an ACK of the second datareceived through the second link.

For example, the order of the first bit and the second bit may bedetermined according to a predefined link order.

For example, the second link of the receiving device may transmit ACKinformation for DATA2 to the first link of the receiving device withinthe SIFS interval after completing the scoreboarding process for thereceived DATA2. The Ack policy included in the first data and/or thesecond data may be Ack Policy Indicator=“00”, which means Normal Ack orimplicit BAR.

For example, after SIFS, the first link of the receiving device, thathas received the scoreboard information (that is, ACK information forDATA2) of the second link of the receiving device, may respond in theform of ACK 1+ACK 2 by combining it with ACK information for DATA1received by the first link. That is, after SIFS, the first link of thereceiving device may transmit an ACK frame (for example, ACK1+ACK2) inwhich ACK information for DATA (for example, DATA1) received by its ownlink (that is, the first link) and ACK information for DATA (forexample, DATA2) received from another link (for example, second link)are aggregated. For example, the second link may transmit an ACK frame(for example, ACK 2) including only ACK information for the receivedDATA 2.

The BAR frame (that is, PPDU) may include a PHY header (PHYHDR) and aphysical service data unit (PSDU). PSDU may include MPDU delimiter,MPDU, and Padding fields. The MPDU may include a MAC header, a framebody, and an FCS field. The MAC header may include Frame Control,Duration, RA, TA, BA Control, and BA Information fields. The BA Controlfield may include BA ACK policy, BA Type, Soliciting Link ID bitmap, andTID information (INFO) fields. The request link bitmap field may includeinformation on a link for which ACK is requested. For example, therequest link bitmap field may include link indicator information forwhich ACK is requested.

For example, when configuring the merged ACK frame or selectivelyconfiguring the merged ACK frame in a specific link, the transmittingdevice may transmit information on which links ACK information should bemerged to configure the Block Ack frame to the receiving link of thereceiving device (that is, the link on which the BAR frame is received)through the BAR frame.

For example, the transmitting device may indicate the link ID definedthrough the reserved field of the BA Control field included in the BARframe in a bitmap format. That is, the BA Control field may include aLink ID of a link for which ACK information is requested.

For example, a soliciting ID bitmap field may be sorted based on thedefined link order, descending order or ascending order of ID, and itmay binary indicate whether to request ACK information. For example, thefirst bit may be related to whether to request ACK information for datatransmitted in the first link, the second bit may be related to whetherto request ACK information for data transmitted on the second link, andthe x-th bit may be related to whether to request ACK information fordata transmitted from Link X. For example, it may correspond to each bitof the request link bitmap in the order in which the Link ID is sortedin descending order, and a bit corresponding to each link may includeinformation related to whether to request ACK information for datatransmitted in each link (1-bit information indicating whether ACK isrequested or not). For example, it may correspond to each bit of therequest link bitmap in the order in which the Link ID is sorted inascending order and a bit corresponding to each link may includeinformation related to whether to request ACK information for datatransmitted in each link (1-bit information indicating whether ACK isrequested or not).

The transmitting device may receive the BA frame from the receivingdevice (S4930). For example, the receiving device receiving the BARframe may transmit the merged multi-link block Ack frame based on thescoreboard of the specified link. That is, the receiving device maytransmit the BA frame based on whether decoding of data received in thedesignated link is successful or not.

Some of the detailed steps shown in the examples of FIGS. 48 and 49 maynot be essential steps and may be omitted. In addition to the stepsshown in FIGS. 48 and 49 , other steps may be added, and the order ofthe steps may vary. Some of the above steps may have their own technicalmeaning.

The technical features of the present disclosure described above may beapplied to various devices and methods. For example, the above-describedtechnical features of the present disclosure may be performed/supportedthrough the apparatus of FIGS. 1 and/or 19 . For example, theabove-described technical features of the present disclosure may beapplied only to a part of FIGS. 1 and/or 19 . For example, the technicalfeatures of the present disclosure described above may be implementedbased on the processing chips 114 and 124 of FIG. 1 , may be implementedbased on the processors 111 and 121 and the memories 112 and 122 of FIG.1 , or may be implemented based on the processor 610 and the memory 620of FIG. 19 . For example, the device of the present specification maycomprise a processor; and a memory coupled to the processor, wherein theprocessor is configured to: receive first data through a first link andreceive second data through a second link, from a transmitting device;receive a first block acknowledgment request (BAR) frame through thefirst link and receive a second BAR frame through the second link, fromthe transmitting device, wherein the first BAR frame and the second BARframe include information related to a link for which an acknowledgement(ACK) is requested; and transmit a first block acknowledgment (BA) framethrough the first link and transmit a second BA frame through the secondlink.

The technical features of the present disclosure may be implementedbased on a computer readable medium (CRM). For example, a CRM proposedby the present disclosure may store instructions which performoperations including the steps of receiving first data through a firstlink and receiving second data through a second link, from atransmitting device; receiving a first block acknowledgment request(BAR) frame through the first link and receiving a second BAR framethrough the second link, from the transmitting device, wherein the firstBAR frame and the second BAR frame include information related to a linkfor which an acknowledgement (ACK) is requested; and transmitting afirst block acknowledgment (BA) frame through the first link andtransmitting a second BA frame through the second link.

The instructions stored in the CRM of the present disclosure may beexecuted by at least one processor. At least one processor related toCRM in the present disclosure may be the processors 111 and 121 or theprocessing chips 114 and 124 of FIG. 1 , or the processor 610 of FIG. 19. Meanwhile, the CRM of the present disclosure may be the memories 112and 122 of FIG. 1 , the memory 620 of FIG. 19 , or a separate externalmemory/storage medium/disk.

The foregoing technical features of this specification are applicable tovarious applications or business models. For example, the foregoingtechnical features may be applied for wireless communication of a devicesupporting artificial intelligence (AI).

Artificial intelligence refers to a field of study on artificialintelligence or methodologies for creating artificial intelligence, andmachine learning refers to a field of study on methodologies fordefining and solving various issues in the area of artificialintelligence. Machine learning is also defined as an algorithm forimproving the performance of an operation through steady experiences ofthe operation.

An artificial neural network (ANN) is a model used in machine learningand may refer to an overall problem-solving model that includesartificial neurons (nodes) forming a network by combining synapses. Theartificial neural network may be defined by a pattern of connectionbetween neurons of different layers, a learning process of updating amodel parameter, and an activation function generating an output value.

The artificial neural network may include an input layer, an outputlayer, and optionally one or more hidden layers. Each layer includes oneor more neurons, and the artificial neural network may include synapsesthat connect neurons. In the artificial neural network, each neuron mayoutput a function value of an activation function of input signals inputthrough a synapse, weights, and deviations.

A model parameter refers to a parameter determined through learning andincludes a weight of synapse connection and a deviation of a neuron. Ahyper-parameter refers to a parameter to be set before learning in amachine learning algorithm and includes a learning rate, the number ofiterations, a mini-batch size, and an initialization function.

Learning an artificial neural network may be intended to determine amodel parameter for minimizing a loss function. The loss function may beused as an index for determining an optimal model parameter in a processof learning the artificial neural network.

Machine learning may be classified into supervised learning,unsupervised learning, and reinforcement learning.

Supervised learning refers to a method of training an artificial neuralnetwork with a label given for training data, wherein the label mayindicate a correct answer (or result value) that the artificial neuralnetwork needs to infer when the training data is input to the artificialneural network. Unsupervised learning may refer to a method of trainingan artificial neural network without a label given for training data.Reinforcement learning may refer to a training method for training anagent defined in an environment to choose an action or a sequence ofactions to maximize a cumulative reward in each state.

Machine learning implemented with a deep neural network (DNN) includinga plurality of hidden layers among artificial neural networks isreferred to as deep learning, and deep learning is part of machinelearning. Hereinafter, machine learning is construed as including deeplearning.

The foregoing technical features may be applied to wirelesscommunication of a robot.

Robots may refer to machinery that automatically process or operate agiven task with own ability thereof. In particular, a robot having afunction of recognizing an environment and autonomously making ajudgment to perform an operation may be referred to as an intelligentrobot.

Robots may be classified into industrial, medical, household, militaryrobots and the like according uses or fields. A robot may include anactuator or a driver including a motor to perform various physicaloperations, such as moving a robot joint. In addition, a movable robotmay include a wheel, a brake, a propeller, and the like in a driver torun on the ground or fly in the air through the driver.

The foregoing technical features may be applied to a device supportingextended reality.

Extended reality collectively refers to virtual reality (VR), augmentedreality (AR), and mixed reality (MR). VR technology is a computergraphic technology of providing a real-world object and background onlyin a CG image, AR technology is a computer graphic technology ofproviding a virtual CG image on a real object image, and MR technologyis a computer graphic technology of providing virtual objects mixed andcombined with the real world.

MR technology is similar to AR technology in that a real object and avirtual object are displayed together. However, a virtual object is usedas a supplement to a real object in AR technology, whereas a virtualobject and a real object are used as equal statuses in MR technology.

XR technology may be applied to a head-mount display (HMD), a head-updisplay (HUD), a mobile phone, a tablet PC, a laptop computer, a desktopcomputer, a TV, digital signage, and the like. A device to which XRtechnology is applied may be referred to as an XR device.

The claims recited in the present specification may be combined in avariety of ways. For example, the technical features of the methodclaims of the present specification may be combined to be implemented asa device, and the technical features of the device claims of the presentspecification may be combined to be implemented by a method. Inaddition, the technical characteristics of the method claim of thepresent specification and the technical characteristics of the deviceclaim may be combined to be implemented as a device, and the technicalcharacteristics of the method claim of the present specification and thetechnical characteristics of the device claim may be combined to beimplemented by a method.

1. A method performed by a receiving device in a wireless local areanetwork system, the method comprising: receiving first data through afirst link and receiving second data through a second link, from atransmitting device; receiving a first block acknowledgment request(BAR) frame through the first link and receiving a second BAR framethrough the second link, from the transmitting device, wherein the firstBAR frame and the second BAR frame include information related to a linkfor which an acknowledgement (ACK) is requested; and transmitting afirst block acknowledgment (BA) frame through the first link andtransmitting a second BA frame through the second link.
 2. The method ofclaim 1, wherein the first BAR frame includes information related to thefirst and second links, and wherein the first BA frame includesinformation related to an acknowledgment (ACK) of the first data and thesecond data.
 3. The method of claim 2, wherein the second BAR frameincludes information related to the second link, and wherein the secondBA frame includes information related to an ACK of the second data. 4.The method of claim 1, wherein the method further comprising, receiving,by the receiving device, third data through the second link from thetransmitting device, wherein the first BAR frame includes informationrelated to the first link and the second link, and wherein the first BAframe includes information related to an acknowledgment (ACK) of thefirst data, the second data, and the third data.
 5. The method of claim1, wherein the information related to the link for which the ACK isrequested includes a first bit and a second bit, wherein the first bitincludes information related to whether to request an ACK of the firstdata received through the first link, and wherein the second bitincludes information related to whether to request an ACK of the seconddata received through the second link.
 6. The method of claim 5, whereinthe order of the first bit and the second bit is determined according toa predefined link order.
 7. A receiving device in a wireless local areanetwork system, the receiving device comprising: a transceiver fortransmitting and receiving a radio signal; and a processor coupled tothe transceiver, the processor is configured to: receive first datathrough a first link and receive second data through a second link, froma transmitting device; receive a first block acknowledgment request(BAR) frame through the first link and receive a second BAR framethrough the second link, from the transmitting device, wherein the firstBAR frame and the second BAR frame include information related to a linkfor which an acknowledgement (ACK) is requested; and transmit a firstblock acknowledgment (BA) frame through the first link and transmit asecond BA frame through the second link.
 8. The receiving device ofclaim 7, wherein the first BAR frame includes information related to thefirst and second links, and wherein the first BA frame includesinformation related to an acknowledgment (ACK) of the first data and thesecond data.
 9. The receiving device of claim 8, wherein the second BARframe includes information related to the second link, and wherein thesecond BA frame includes information related to an ACK of the seconddata.
 10. The receiving device of claim 7, wherein the processor isfurther configured to: receive, by the receiving device, third datathrough the second link from the transmitting device, wherein the firstBAR frame includes information related to the first link and the secondlink, and wherein the first BA frame includes information related to anacknowledgment (ACK) of the first data, the second data, and the thirddata.
 11. The receiving device of claim 7, wherein the informationrelated to the link for which the ACK is requested includes a first bitand a second bit, wherein the first bit includes information related towhether to request an ACK of the first data received through the firstlink, and wherein the second bit includes information related to whetherto request an ACK of the second data received through the second link.12. The receiving device of claim 11, wherein the order of the first bitand the second bit is determined according to a predefined link order.13. A method performed by a transmitting device in a wireless local areanetwork system, the method comprising: transmitting first data through afirst link and transmitting second data through a second link, to areceiving device; receiving a first block acknowledgment request (BAR)frame through the first link and transmitting a second BAR frame throughthe second link, from the transmitting device, wherein the first BARframe and the second BAR frame include information related to a link forwhich an acknowledgement (ACK) is requested; and receiving a first blockacknowledgment (BA) frame through the first link and receiving a secondBA frame through the second link. 14-16. (canceled)